Continental Motors GO-300-A User manual

Publication X30019
©2011 CONTINENTAL MOTORS, INC. AUG 2011
GO-300-A, C, D & E
CONTINENTAL®AIRCRAFT ENGINE
OVERHAUL
MANUAL
FAA APPROVED

A GO-300 Series Engine Overhaul Manual
31 August 2011
Supersedure Notice
This manual revision replaces the front cover and list of effective pages for Publication Part No. X30019, dated
August 1981. Previous editions are obsolete upon release of this manual.
Effective Changes for this Manual
0.................August 1981
1............31 August 2011
List of Effective Pages
Document Title: GO-300 Series Engine Overhaul Manual
Publication Number: X30019 Initial Publication Date: August 1981
Page Change Page Change Page Change Page Change
Cover............................1
A...................................1
i Blank added ...............1
ii thru vi.........................0
1 thru 67.......................0
Published and printed in the U.S.A. by Continental Motors, Inc.
Available exclusively from the publisher: P.O. Box 90, Mobile, AL 36601
Copyright © 2011 Continental Motors, Inc. All rights reserved. This material may not be reprinted, republished, broadcast, or otherwise
altered without the publisher's written permission. This manual is provided without express, statutory, or implied warranties. The publisher will
not be held liable for any damages caused by or alleged to be caused by use, misuse, abuse, or misinterpretation of the contents. Content is
subject to change without notice. Other products and companies mentioned herein may be trademarks of the respective owners.

INTENTIONALLY
LEFT
BLANK

ii
Section
I
n
III
IV
V
VI
vn
VIll
IX
X
XI
XII
XllI
XIV
XV
Table
I
n
III
IV
V
VI
VII
VIll
IX
X
XI
Xll
XllI
XIV
XV
XVI
XVII
XVIII
XIX
TABLE OF CONTENTS
Introduction •.•.•••.•••
Specifications, Limits and Charts
General Description • . • . . . • .
Unpacking
and Preparation for Service, storage or Shipment
Installation in Aircraft and Removal
Maintenance Instructions
Disassembly
Cleaning Parts •••••
Inspection . . • • • .
Repair and Replacement
Assembly of Subassemblies
Final Assembly • • • • • . •
Repair and Testing of Accessories •
Testing After Overhaul
Table of Limits • • . . • . • • . •
LIST OF TABLES
Purchased Accessories
Ignition System Details
Characteristics and Dimensions •
Fuel System Details
Temperature Limits • •
Pressure Limits • • • • •
Oil Viscosity Grades • •
Trouble Shooting Chart
Magnaflux Inspection Thl.ta
Critical New Parts Dimensions
Stud Identification ••
stud Setting Heights ••••••
Test Operating Limits
Top or Minor Overhaul Test Run
Major Overhaul Test Run. • • • • •
Table of Limits .•••••••.
Table of Tightening Torques • • • •
General Use -Tightening Torques
Pipe Plugs •••••••••••.•
Page
I
2
4
8
9
12
21
32
34
39
46
49
53
55
59
Page
2
2
2
3
3
3
3
15
34
36
40
40
56
57
57
58
62
63
63

LIST OF ILLUSTRATIONS
Figure
1 Three-Quarter Right Front View of Model GO-300-A Aircraft Engine
2
Three-Quarter Left Rear View of Model GO-300-A Aircraft Engine
3
Gear Train Diagram • . • • • • .
4
Section through Hydraulic Tappet
5 Installation Drawing
6
starter and Adapter
7 Ignition System and Accessories
8 Induction System & Oil Sump •
9
Cylinder & Piston
10 Propeller Reduction Gear Unit •
11
Crankcase
12 Left Crankcase Mounted on Engine stand
13 Crankcase Cover • • . • • • . •
14
Cylinder Dimensional Drawing
15 Installing Helical Coil Inserts
16 Rocker Arm Bearing Dimensions
17 Measuring of Dampener Bushing
18 Connecting Rod
and Bushing Dimensions
19 starter Adapter Bearing Installer •
20
Installing starter Adapter Bearing
21 Installation of Valve Spring Locks
22
23
Installing Propeller Shaft Oil Seal
Installing Propeller Shaft Oil Seal Spring
24 Alignment of Timing Marks ••
25 Limits and Lubrication Chart
26 Limits and Lubrication Chart
27 Limits and Lubrication Chart
28 Limits and Lubrication Chart •
Page
v
vi
6
7
10
22
23
24
25
27
28
29
30
38
41
42
...... 42
43
43
44
46
48
48
50
64
65
66
67
iii

iv
Term
A.B.C. :
Approx. :
A.T.C. :
Bar. :
B.B.C. :
B.H.P. :
B.T.C. :
C.A.R. :
c.f.m. :
C.G. :
Dia. :
o.
OF:
F.A.A.
Fig. :
Front:
ft. :
G.P.M. :
H20 :
Hg. :
I.D. :
in. (It) :
Hex. :
hr. :
Left Side:
Lbs. :
Lock wire:
Man. :
Min. :
30' :
N.P.T. :
N.C. :
N.F. :
O.D. :
Press.:
p.s.i. :
Rear:
Right Side:
R.P.M. :
Std. :
T.D.C. :
Temp. :
Torque:
DEFINITIONS AND ABBREVIATIONS
Explanation
After Bottom Center
Approximate ly
After Top Center
Barometric
Before Bottom Center
Brake Horsepower
Before Top Center
Civil Air Regulations
Cubic feet per minute
Center of Gravity
Diameter
Degrees of Angle
Degrees Fahrenheit
Federal Aviation Administration
Figure (Illustration)
Propeller End
Foot or feet
Gallons per minute
Water
Mercury
Inside Diameter
Inches
Hexagon
Hour
Side on which No.' s 2, 4 and 6 cylinders are located
Pounds
Soft steel wire used to safety connections, etc.
Manifold or manometer
Minimum
Thirty minutes of angle (60' equal one degree)
National pipe thread 1tapered)
National Coarse (thread)
National Fine (thread)
Outside Diameter
Pressure
Pounds per square inch
Accessory end of engine
Side on which No.'s 1, 3 and 5 cylinders are located
Revolutions per minute
Standard
Top dead center
Temperature
Force x lever arm (125 ft. -lbs. torque = 125 lbs. force
applied one ft. from bolt center or 62-1/2 lbs. applied
2 ft. from center)

11
12
13
14
1. No. 1 cylinder upper ignition cable
14. Manifold riser
2. No. 3 cylinder 15. Vacuum pump drive cover
3. No. 3 cylinder upper ignition cable
16. Right front mount bracket
4. No. 5 cylinder upper ignition cable
17. No. 5 cylinder inta"ke pipe
5. No. 5 cylinder
18. No. 5 cylinder lower ignition cable
6. Oil cooler 19. Carburetor
7. Propeller reduction unit housing 20.
Throttle lever
8. Propeller shaft bearing cage
21. No. 3 cylinder intake pipe
9. Propeller shaft oil seal
22. No. 3 cylinder lower ignition cable
10. Propeller shaft 23. Right rear mount bracket
11. Vernatherm valve 24. No. 1 cylinder lower ignition cable
12. Crankshaft cover 25. No. 1 cylinder intake pipe
13. Accessory drive front cage
26. No. 1 cylinder
Figure 1. Three-Quarter Right Front View of Model GO-300-A Aircraft Engine
v

1. No. 6
cylinder upper ignition cable 23.
Bolt, lockwasher and washer
2. No. 4
cylinder upper ignition cable 24. Generator blast tube
3.
Crankcase breather 25. Oil screen
4. No. 2
cylinder upper ignition cable 26. Oil screen
5.
Two-wire ignition cable bracket 27. Balance tube
6.
Lifting eye 28. Mixture control lever
7. Oil
filler cap 29.
Crankcase cover
8. Oil
filler neck 30. Bolt, lockwasher and washer
9.
Three-wire ignition cable bracket
31. Oil
sump drain plug
10. Nut,
lockwasher and washer 32. Oil gauge rod
11. Nut,
lockwasher and washer 33. Oil sump
12.
Starter 34.
Left rear mount bracket
13.
Three-wire ignition cable bracket
35. No. 2
cylinder intake pipe
14. Nut,
lockwasher and washer
36.
Two-wire ignition cable bracket
15.
Left magneto
37. No. 2
cylinder lower ignition cable
16. Wire harness band
38. No. 2 cylinder
17. Right magneto 39. No. 4 cylinder lower ignition cable
18.
Magneto switch wire terminals
40. No. 4
cylinder intake pipe
19. Nut,
lockwasher and washer
41. No. 6 cylinder lower ignition cable
20. Nut,
lockwasher and washer 42. No. 4
cylinder
21. Nut
and washer
43. No. 6
cylinder intake pipe
22.
Generator 44. No. 6 cylinder
Figure 2. Three-Quarter Left Rear View of Model GO-300-A Aircraft Engine
vi

SECTION
INTRODUCTION
1-1. SCOPE.
1- 2. Material in this publication is applicable to model
GO-300-A,B,C,D and E aircraft engines. A brief
explanation of construction features and functional
systems is included. This information is supple-
mented by the Limits and Lubrication Chart, which
is composed of sectional drawings printed on the
final pages. Tables of specifications, performance
characteristics, operation limitations and perform-
ance charts are included in Section II. Dimensional
specifications in the Table of Limits govern the
permissible tight fits of "permanently" assembled
parts and clearances of running parts as a guide
for the determination of service-ability at overhaul.
Other sections are devoted to instructions for opera-
tion, inspection, routine maintenance, trouble shooting
and
overhaul procedure. Description, text, specifi-
cations and part numbers mentioned herein are
correct as of the date of publication;however, changes
may be made in specifications and/or part numbers.
Therefore, all replacement parts should be ordered
in accordance with information contained in the Spare
Parts Catalog, Form X-30020, and operation limita-
tions herein should not be construed to authorize
any departure from limits published in the applicable
F .A.A. Type Specification. If more detailed infor-
mation is necessary concerning any of the purchased
accessories listed in Table I, it is requested that
inquiries for such be made of the manufacturer or
agency whose name and address is listed immediately
behind the accessory in Table I.
1-3. AVAILABILITY.
1-4. Further copies of this and other Continental
aircraft engine service publications may be purchased
through Continental
Approved Distributors and PartsDealers
of aircraft engine parts. It is requested that all orders fMsuch
publications be placed with these facilities when not
immediately available from their stock.
1-5. SERVICE BULLETINS.
1-6. Important changes in part numbers, interchange-
ability of parts, urgent inspections, mandatory re-
placements and modernization information are among
the subjects of limited interest and duration covered
by factory Service Bulletins, which are distributed to
all Approved Distributors of aircraft engines and
parts and are available for study at their offices.
Service Bulletins of interest to aircraft owners,
operators and maintenance personnel may be obtained
by
direct mail on an annual subscription basis. The
charge for this service covers only postage and handling.
Subscriptions are received
by the factory Publications
Department, to whom inquiries on this subject may be
addressed.
1-7. SERVICE REPORTS AND INQUIRIES.
I-S. It is the policy of Teledyne Continental Motors to
handle all reports of service difficulty and requests for
information through
Approved Distributors. These facilities
are constantly in touch with operation and repair. You will
find
them more than willing to help solve your maintenance
problems and well equipped with experience and facilities to
perform any necessary maintenance work on Continental
aircraft engines.
There is an Approved Distributor at every
major airport.
COMPARATIVE LIST OF MODEL DIFFERENCES
FEATURE GO-300-A
GO-300-B
GO-300-C
GO-300-D
GO-300-E
Starter Manual Manual Manual Right angle Right angle
engagement
engagement
engagement
automatic
automatic
engagement
engagement
Crankcase
Flange mounted Flange mounted
Pressed in Pressed in
Pressed in
Breather
Vacuum
Pump
Lower right
Lower right
Lower right
Rear of Rear of
Drive Side of reduc-
side of reduc-
side of reduc-
starter starter
hon housing
tion housing
tion housing
adapter
adapter
Propeller None
Upper rear
of None None
Upper rear
of
Governor Drive
reduction reduction
housing housing
1

Accessory
Carburetor
Magneto
Magneto
(Optional)
Spark Plug
Starter
Starter
Generator
Regulator
Oil Cooler
SECTION II
SPECIFICATIONS, LIMITS AND CHARTS
TABLE I PURCHASED ACCESSORIES
Manufacturer
Marvel-Schebler Div., Borg Warner Corp.
Slick Magneto Co. , Rockford Illinois
Bendix
AC Spark Plug Company
Delco-Remy Div., General Motors Corp.
Delco-Remy Div., General Motors Corp.
Delco-Remy Div., General Motors Corp.
Delco-Remy Div., General Motors Corp.
Harrison Radiator Div.,General Motors Corp.
TABLE II IGNITION SYSTEM DETAILS
Model or
Serial No.
MA-4-5
667
S6RN-21
SR-87
1109677
1109514
1101910
1118736
8531835
Feature Value
Left magneto fires lower right and upper left side plugs
Right magneto fires upper right and lower left side plugs
Firing order (cylinder numbers)
Spark plug gap settings SR-87
Permissible R.P.M. spread when switched from
"Both" to either "Left" or "Right" magneto
TABLE III CHARACTERISTICS AND DIMENSIONS
280 B.T.C.
28
0
B.T.C.
1,4,5,2,3,6
.018 - ,022 in.
100
R.P.M.
Oty
1
2
2
12
1
1
1
1
1
------------~~-------------------- -------------------------------------
2
Dimension
Piston strokes per cycle
Number of cylinders
Cylinder bore (in.)
Piston stroke (in.)
Compression ratio
Total displacement (in.)
Propeller gear reduction
Over-all length (in.) A, B & C
Value
4
6
4.0625
3.875
7.3:1
301.37
0.75:1
39.12
Dimension
Value
Over-all length (in. ) D,
E 39.19
Over-all width (in.) 31.50
Over-all height (in.) GO-300-A,-B
27.62
Over-all height (in.) GO-300-C, -D,-E
26.56
Number of mounting brackets
4
Rated maximum crankshaft R.P.M. 3200
Rated maximum B.H.P. 175
Total dry weight (lbs.) 311. 92

TABLE IV FUEL SYSTEM DETAILS
Feature Value
Minimum fuel octane rating 80/87
Fuel pressure required (psi)
Fuel inlet to carburetor (N.P.T.)
Venturi diameter
0.5 - 6.0
1/4 in.
1-13/16 in.
TABLE V TEMPERATURE LIMITS
Indicated Condition
Minimum
Maximum
Oil temperature at take-off ........•....
Oil temperature in flight ....................•.•....
Desired oil temperature ...........•.•.............
2000 F
Cylinder head temperature (downstream spark plug gasket) •...
Cylinder base temperature (bayonet thermocouple)* ...•.•..
Magneto temperature (at coil hold-down screw) A, B, C & D.
Magneto temperature (at coil hold-down screw) E •••••••
* Installed in tapped hole in bottom of cylinder head. Applicable only with downdraft cooling system.
TABLE VI PRESSURE LIMITS
Indication
Minimum
Maximum
Oil pressure (idling) 5
p.s.i.
Oil pressure (in flight) 30 p.s.i.
60 p.s.i.
TABLE VII OIL VISCOSITY GRADES
Ambient Air Temperature
S.A.E. Grade
Below 400F
30
Above 40°F
50
Ambient air temperature is the controlling factor on
all engines having Vernatherm valves installed.
2-1. OIL SUPPLY AND MEASUREMENTS.
2-2. The capacity of the oil sump is 10 U.S. quarts.
The minimum quantity of oil in the sump necessary to
adequately lubricate the engine at 20
0
nose up to 150
nose down attitudes of flight is 7 U.S. quarts. The oil
filler cap is marked "OIL 10 QUARTS". It is attached
over the oil filler neck which is located on the upper
left side of the crankcase cover. The oil sump is
equipped with an oil level gauge which is graduated in
2-quart increments and stamped with the numerals 4
through 10. The oil gauge is located on the crankcase
left side between No. 2 cylinder and the crankcase
cover.
2-3. OIL FLOW, HEAT REJECTIONANDCONSUMP-
TION.
2-4. When operated on a rigid test stand, at normal
rated power and speed, with an oil inlet temperature
of 2200 F (with S. A. E. 50 oil) and oil pressure of 35
p. s. i. (plus or minus 2 p. s. i.) oil flow shall not ex-
ceed 50 lbs. per minute. Heat rejection to the oil
shall not exceed 280 BTU's per minute at 3200 rpm.
Oil consumption shall not exceed 2.75 lbs. per hour
at 3200 rpm.
3

SECTION III
GENERAL DESCRIPTION
3-1. CONSTRUCTION.
3-2. GENERAL. The arrangement and appearance
of engine parts and components are illustrated in
figures 1 and 2. Additional information will be found
in
the installation drawing andin the limits and lubri-
cation charts.
3-3. CRANKCASE. Two aluminum alloy castings are
joined along the vertical center plane to form the com-
plete crankcase, The individual castings (with studs
and inserts) will be called "the left crankcase" and
"the right crankcase" throughout this publication.
The two
crankcase halves are aligned one to the other
by the use of eight dowel type through bolts. Four of
the bolts are above the crankshaft centerline and four
below.
3-4. Bosses molded in the crankcase castings are
line bored, in the assembled castings, to form bear-
ings for the camshaft and seats for precision, steel
backed, lead alloy lined crankshaft main bearing in-
serts. Guides are bored through lateral bosses for
the hydraulic valve lifters,
3-5. Cylinder mounting pads on the left crankcase
are farther forward than corresponding pads on the
right crankcase to permit each connecting rod to work
on a separate crankpin, Each pad has two holes for
crankcase through bolts and four studs for the attach-
ment of cylinder flanges. Two engine mount brackets
are attached to studded pads on the side of each crank-
case. (See 16 and 23, figure 1. )
3 -6, CRANKSHAFT. The six-throw steel alloy forg-
ing is machined all over excepting some surfaces of
the crankcheeks. Main journals and crankpins are
nitrided after grinding. The crankcheeks between
No's. 1 and 2, 3 and 4, 5 and 6 crankpins have side
blades, each equipped with two hardened steel bushings
for steel pins on which one of the pendulum counter-
weights is mounted. Oscillation of the counterweights
on their pins damp out crankshaft torsional vibration
at the gear end. The rear end of the crankshaft is
tapped and doweled to provide features for the attach-
ment of the crankshaft gear. The front end of the
crankshaft has an internal spline which receives and
drives the reduction unit quill shaft.
3-7. The crankshaft gear is heated prior to installa-
tion to obtain a shrunk fit with the crankshaft. The
gear is driven by a pilot dowel of uniform diameter,
The gear is retained by four 1/ 4-inch retaining bolts.
3-8. CONNECTINGRODS. Automotive-type connect-
ing rods have split bronze piston pin bushings and two
identical precision inserts (of the same type as main
bearings) at the crankpin end. Weight variation of
rods in any engine set is limited to YS ounce in opposite bays.
4
3-9. CAMSHAFT. A steel alloy forging is machined
on
four journals, nine cam lobes and the gear mount
flange
at the rear end. The lobes and journals are
ground and hardened. A groove around the front
journal passes engine oil from the right crankcase
cross passage to the left case passage. The camshaft
gear is attached by four unequally spaced bolts to
locate its timing mark in relation to the lobes. The
male half drive coupling at the front of the shaft mates
with and drives the front accessory drive gear on
Model GO-300-A, Band C engines.
3-10. PROPELLER REDUCTION HOUSING. The
aluminum alloy propeller reduction housing mounted
on the
front of the engine contains front support bear-
ing for the propeller shaft drive gear, the accessory
drive gear, the accessory drive gear assembly, the
propeller shaft rear bearing and the Vernatherm
valve. The GO-300-B and E contain governor drive
gears. Mountedon the top of the housing is the crank-
case breather. For Model GO-300-A and B, the
breather assembly is attached toa studded pad by four
sets of attaching parts. For all other models, the
breather is pressed into the housing. Mounted on the
right side of the housing is the oil cooler and on the
upper front is the propeller shaft cage assembly. The
cage assembly contains the propeller shaft and its
bearings. A rubber composition oil seal, held tightly
between
the cage halves, is sealed to the shaft by a
helical spring inside the seal's cavity. A felt dust
shield is cemented to the front of the oil seal to pre-
vent abrasive materials working under the seal lip and
scoring the shaft,
3-11. PISTONS, PINSANDRINGS. Pistons are heat-
treated aluminum alloy casting with cam ground skirts.
The top ring groove is fitted with a chrome-faced cast
iron ring. The second ring groove is fitted with a
plain cast iron ring, while the third and fourth grooves
have tin-plated cast iron rings. The fourth, or oil
control, ring is a slotted type. Oil drain holes are
drilled through the piston just below and on a 30° angle
to
the third compreSSion ring. The full-floating piston
pin is a case hardened, seamless, alloy steel tube
with pressed in aluminum end plugs. The plugs are
machine finished after assembly and the pin is ground
to
final size and polished.
3-12. CYLINDERS. Heat-treated aluminum alloy
cylinder heads are screwed and shrunk onto the forged
steel barrels. Cooling fins on both the cylinder head
and
barrel provide ample heat dissipating surface with
a
minimum reSistance to air flow. Cylinder bores
are ground to a specific surface finish. Helical coil
thread inserts are installed in the spark plug holes.
Rocker boxes are integrally cast in the cylinder head
and
are provided with lightweight cadmium-plated
covers. Both intake and exhaust ports are on the
downward
side when the cylinder is installed.

3 -13. OIL SUMP. The oil sump is an aluminum alloy
casting. An integral intake manifold riser was cast
into the sump on the earlier models. This manufac-
turing process has been revised. On current sump
assemblies, the riser is now a sheet metal tube, per-
manently sealedin place by beaded ends. A machined
and studded pad at the front of the sump provides a
mounting
surface for the manifold riser. A similar
pad located on the sump, lower rear, provides for the
attachment of the updraft carburetor. The rear sur-
face of the sump is machined, drilled and tapped for
crankcase cover attaching parts. The current sump
assembly utilizes a removable oil suction tube in lieu
of the cored, integral suction passage, used in earlier
production sumps.
3-14. The magnesium alloy crankcase cover casting
at the rear of the engine houses the oil pump, suction
and pressure oil screens, pressure relief valve, cam-
shaft and crankshaft gears. The oil filler neck is on
the
upper left, the oil screen's lower center and the
relief valve center right. studdedmount pads are pro-
vided on the cover's rear surface for two magnetos,
starter, generator and tachometer drive housing. The
crankcase cover extends over the rear end of the sump
and is attached to it by bolts, lockwashers and washers.
The crankcase cover is attached to the crankcase by
studs, projecting from the crankcase, washers, lock-
washers and nuts. A gasket seals the joint at the
mating surfaces of the crankcase, cover and sump.
3-15. FUNCTIONAL SYSTEMS.
3-16. GEAR TRAIN. (See Figure 3.) The crankshaft
gear, which is turned in a counterclockwise direction
by the crankshaft, turns the camshaft gear clockwise.
The squared end of the oil pump and tachometer drive
shaft is inserted in the square center hole of the cam-
shaft gear and is turned in a clockwise direction. The
magneto drive gears are driven in a counterclockwise
direction by the camshaft gear. The generator drive
gear is driven in a clockwise direction by the inner
ring of gear teeth of the camshaft gear. The starter
pinion rotates clockwise to turn the crankshaft gear
counterclockwise. The propeller shaft drive gear is
joined to, and driven by, the crankshaft through a quill
shaft. The propeller shaft drive gear rotating in a
counterclockwise direction drives the propeller shaft-
gear and shaft in a clockwise direction.
3-17. LUBRICATION SYSTEM. From the lowest
point in the sump, oil enters the lubrication system
through a suction passage, or tube, to the oil suction
screen in the crankcase cover. From the oil screen
cavitya cored passage leads to the suction side of the
oil pump. From the pressure side of the pump a cored
passage conducts the oil to another cored passage in
the sump which in turn directs the pressurized oil to
the right crankcase main gallery. The main gallery
is a cored hole extending the full length of the crank-
case. The rear exit of the gallery is aligned with a
passage to the oil pressure relief valve. The front
exit of the gallery aligns with the entrance to a passage
in the reduction unit housing which directs the oil to
the inlet side of the oil cooler.
3-18. The oil cooler mount pad, on the reduction unit
housing, is formed so as to provide separate inlet and
outlet compartments when the cooler is installed. Oil
flows
from the inlet, or lower, compartment into the
bottom of the cooler, circulates upward through the
cooler and empties into the outlet, or upper, compart-
ment. A vertical passage directs the oil from the out-
let compartment down to and around the Vernatherm
valve. The temperature of the oil affects the length
of
the Vernatherm valve. As the temperature of the
oil lowers, the length of the valve decreases, thus
opening a
direct oil passage from the oil cooler inlet
compartment to the Vernatherm valve cavity and in
so dOing, bypasses the oil cooler. As oil temperature
rises, the valve expands in length, thus closing the
direct passage, and routing the oil through the cooler.
3-19. From the Vernatherm cavity, oil passages
direct the oil to the bearings of the reduction unit
housing. The
main supply of lubricating oil is con-
ducted through passages of the housing to a hole at
the right rear side which aligns with a Similar hole in
the right crankcase. As the oil re-enters the right
crankcase it is directed to the front camshaft bearing.
The front camshaft bearing journal is grooved to per-
mit the oil to pass freely to a passage in the left
crankcase. The passage in the left crankcase directs
the oil from the camshaft bearing to the left crankcase
main gallery.
3-20. From the left crankcase gallery oil is directed
to the intermediate and rear camshaft bearings and to
the crankshaft main bearings. Oil is conducted from
the crankshaft main bearings to the connecting rod
bearings through steel tubes which are permanently
installed in the crankshaft.
3-21. VALVE MECHANISM. (See Figure 4.) Oil is
fed to the hydraulic valve lifters through passages
drilled from the lifter guides to the main oil galleries.
The lifters are composed of four main parts; the cup,
cylinder, piston and body. The piston and cylinder
are not interchangeable. The lifters are automatically
adjusted to function properly with valve lash ranging
from .030 inch to . 110 inch between the valve stem
end and rocker arm with the lifter fully deflated. Oil
under pressure from the lubricating system of the
engine is supplied to the hydraulic lifter through hole
(H) to supply chamber (J).
3-22. With face oflifter on the base circle of the cam,
and the engine valve seated as shown in figure 4, the
light plunger spring (K) lifts the hydraulic plunger (C)
so that its outer end contacts pushrod, taking up the
clearance at this point and all along the valve train,
giving zero lash. As the plunger (C) moves outward,
increasing the vol u m e in the pressure adjusting
chamber (L), the ball check valve (D) moves off its
seat and oil from the supply chamber (J) flows in and
fills chamber (L).
5

1. Crankshaft gear, rotates at engine speed counterclockwise
2. Camshaft gear, rotates at 1/2 engine speed clockwise
3. Magneto drive gears, rotates at 1-1/2 engine speed counterclockwise
4. Oil pump drive gear, rotates at 1/2 engine speed clockwise
5. Oil pump driven gear, rotates at 1/2 engine speed counterclockwise
6. Generator drive gear, rotates at 2.035:1 engine speed clockwise
7. Starter gear, rotates at 5.111 engine speed clockwise
Figure 3. Gear Train Diagram
6

L
•
Figure 4. Section through Hydraulic Tappet
3-23. As the camshaft rotates, the cam pushes the
lifters body outward, tending to decrease the volume of
chamber (L) and forcing the ball check onto its seat.
Further rotation of the camshaft moves the lifter
body (A) outward and the confined body of oil in
chamber (L) acts as a member in the valve operating
mechanism, the engine valve being lifted on a column
of oil. So long
as the engine valve is off its seat, the
load is carried by this column of oil.
3-24. During the interval when the engine valve is off
its seat, a pre-determined slight leakage occurs
between plunger and cylinder bore, which is necessary
to compensate for any expansion or contraction occur-
ring in the valve train. Immediately after the engine
valve closes, the amount of oil required to refill the
adjusting chamber (L) flows in from the supply chamber
(J), thus establishing the proper length of oil column to
maintain zero lash during the next cycle.
3-25. The basic principle ofthe hydraulic lifter is that
it provides, between the cam and the pushrod, a column
of oil which carries the load while the engine valve is
off its seat, and the length of which is automatically
adjusted so that each camshaft cycle gives zero lash.
3-26. The pushrod assemblies are made up of light-
weight steel tubes with pressed-in ball ends. The ball
ends are drilled to provide an oil passage from the
valve lifters to the rocker arm. The rocker arms
are drilled to provide an oil passage from the push-
rod end to the rocker arm bearings. Oil is sprayed
from the rocker arm to lubricate the valve springs
and valve guides. Oil is returned to the crankcase
by flowing through the pushrod housings.
3-27. IGNITION SYSTEM. High voltage current is
generated and distributed to the upper spark plugs
of
the right side cylinders and lower spark plugs
of
the left side cylinders by a magneto mounted on
the right side of the crankcase cover. An identical
magneto mounted on the left side of the crankcase
cover produces the current for the upper spark plugs
of
the left side cylinders and lower spark plugs of
the right side cylinders. The high tension cables
pass through braided, flexible, shielded conduit as-
semblies which are connected to the magneto by
coupling nuts and
to the spark plugs by elbows. The
magnetos are driven through impluse couplings which
incorporate springs and counterweighted latches. At
cranking speed, the latches engage magneto body
stops to retard the rotors and ignition spark. Re-
tarding the magneto rotors at cranking speed serves
to retard ignition spark until the piston reaches top
center at the beginning of the power stroke and to
attain full secondary coil voltage as the rotor is spun
rapidly through the breaker opening position at which
the spark occurs. As engine speed increases, cen-
trifugal force disengages the latches, and the mag-
netos are driven at full advance.
7

SECTION IV
UNPACKING AND PREPARATION FOR SERVICE, STORAGE OR SHIPMENT
4-1. UNPACKING.
4-2. Detach the assembly of shipping crate top and
side panels from the crate base by removingthe nails
around the bottom and side edges; then lift off the
cover assembly. Engines received from the factory
are covered by a moisture proof paper shroud. Lift
off
the shroud and remove from the crate base the
packages containing the spark plugs. Attach a chain
hOist
to the engine lifting eye, located at the top
crankcase flange, before loosening the engine mount
bracket attaching bolts. Take up slack in the holst;
then remove the attaching parts. Lift the engine
straight up until clear of the crate. It is advisable
to support the engine on an assembly stand while re-
moving packing materials and installing accessories.
4-3. Remove dehydrator plugs from the upper spark
plug holes. If the engine is to be installed at once,
turn the crankshaft as necessary, and inspect the
interior of each cylinder with the aid of a flashlight.
If a pool of oil is standing in any cylinder it must be
drained before engine is installed. If compression
can.not be built up inany cylinder by turning the crank-
shaft while the upper spark plug hole is plugged, re-
move the valve rocker cover from that cylinder, and
check valve action. If a valve stem is sticking in its
guide, apply castor oil or engine lubrication oilthinned
with gasoline while the
crankshaft is rotated and until
the valve operates freely. Use a new gasket when re-
placing the valve rocker cover.
4-4. Remove the plastic caps from the breather elbow
and the generator blast tube connector. Remove the
bolts, spacers and cover from each cylinder exhaust
port flange. Remove plastic protectors from spark
plug cable elbows. Remove any moisture proof
adhesive tape installed to cover vent holes during
shipment.
4-5. PREPARATION FOR SERVICE.
4-6. The corrosion-preventive oil fed into the lubri-
cating system and sprayed into cylinders before ship-
ment of a new engine will mix with normal engine
lubricating oil and will do no harm; hence, it does not
need to be flushed out.
4-7. Install sparkplugs and tighten to specifiedtorque. Insert
the cable terminals and screw on the elbow hex couplingnuts.
Tighten coupling nuts only moderately.
4-8. Install the proper type of washer thermocouple
under the lower spark plug of the cylinder specified
by the aircraft manufacturer.
4-9. To install the oil gauge pressure line fitting,
8
remove the 1/8-in. pipe plug located in the crankcase
between No.2 and 4 cylinders. Coat the pipe threads
of the fitting with a thin film of Ledplate #250 before
installing.
4-10.
Install the proper connectorfitting for the intake
manifold
pressure gauge line in the 1/8-inch pipe
tapped hole in
the manifold riser.
4-11. PREPARATION FOR STORAGE.
4-12.
If an engine which has beenin operation is to be
stored much longer than a weekunder normal climatic
conditions, and if periodiC running to circulate oil is
not carried out, it is advisableto prepare it for storag.e
in the following manner:
a. Operate the engine until the oil temperature
reaches the normal range. Drain the oil sump as
completely as possible; then replace the drain plug.
b.
Fill the oil sump to the full (F) mark on the level
gauge with a
corrosion-preventive oil which will mix
with
normal oil and which is suitable as a lubricant.
This oil must be preheated to 225°F. (See Service Bulletin
M81-3 Rev 1.)
c. Run the engine at least five minutes at a speed
between 1200 and 1500 R.P.M. with the oil tempera-
ture between 215 and 225
0
F. The cylinder head tem-
perature must not exceed 4500 F.
d. Inject the same type of corrosion-preventive oil
used in the lubricating system into the carburetor
intake, while the engine is running, at a rate of 1/2
gallon per minute until smoke comes from the exhaust
pipe; then
increase the spray until it stops the engine.
e.
If possible, spray the corrosion-preventive oilinto
the
cylinder exhaust ports.
f. Do not turn the crankshaft at any time after com-
pletion of the preceding steps.
g. Remove all spark plugs, and spray corrosion-
preventive oil, without air, into the upper spark plug
holes, then into the lower
spark plug holes to assure
complete coverage of the interior cylinder surfaces.
This oil should be at a temperature of 150 to 1800 F.
h. Replace the lower spark plugs, or install solid
plugs in their places. Install dehydrator plugs in the
upper
spark plug holes.
t. Install plastic shipping plugs or other suitable
covers on the detached spark plug cable terminals.
Cover all engine and accessory vents and other open-
ings, including the
crankcase breather, with non-
hygroscopic tape
or other vaporproof material.
j. Drain the corrosion-preventive oil from the sump
and
replace the drain plug.
k.
Post a conspicuous warning regarding drainage of
the oil supply
and other measures which must be taken
before operation of the engine. If a propeller is in-
stalled, attach a warning placard against movement.

SECTION V
INSTALLATION IN AIRCRAFT AND REMOVAL
5-1. ACCESSORIES.
5-2. OPTIONAL ACCESSORIES. If a hydraulic pump
or a vacuum pump is to be installed on a GO-300-A,
-B or -C engines, remove the pad cover from lower
right side of reduction unit housing. If the pump is
to be installed on GO-300-D or -E engine, remove
the pad cover from the rear of the starter adapter.
(See figure 6.) Install a new gasket and attach the
pump with plain washers, new lock washers and the original
cover attaching nuts.
If the aircraft has an oil dilution valve,
install
the fitting in place of the plug immediately above the
pressure oil screen in the crankcase cover. For GO-300- Band -
E engines
remove the governor mount pad cover and install
the propeller governor. The governor pad is located on the
upper right rear of the reduction unit housing. Install a new
gasket and attach the governor with plain washers, new lock
washers
and plain nuts.
5-3. INSTALLATION.
5-4. DIMENSIONS. Principal dimensions of the
engine which affect mounting and locations
of control
and instrument connections are shown in the installa-
tion drawing (Figure 5).
5-5. PRECAUTION. The engine assumes a slightly
tail heavy attitude when suspended by its lifting eye.
It may be necessary to hold down on the front end in
order to align the engine mount brackets with attach-
ing brackets of the aircraft. Make sure that the
mount bushings
all contact the aircraft brackets
uniformly and seat fully on the engine mount bracket
when the mounting bolts are installed. Tighten the
mounting
bolts to the torque specified by the aircraft
manufacturer.
5-6. CONTROL CONNECTIONS. The magneto switch
wires should be installed first. Before installing
the switch wire terminals in the magneto sockets, check
each with a buzzer and battery for continuity with the
switch in
"LEFT" and "RIGHT" positions. Remember
that the left magneto should be grounded through the
switch when the switch is turned to "RIGHT" pOSition
and the right magneto should be grounded with the
switch in the "LEFT" position. This is important
when shooting ignition troubles. Connect the wires to
the magnetos.
5-7. Connect the throttle and mixture controls where
indicated on installation drawing and check each for
full
range of operation. For GO-300-A, -B and -C
engines, connect the
starter detent cable to the lever,
on the starter, then operate the control to make
certain the starter pinion is fully engaging the crank-
shaft gear. On all models connect the electrical lead
to the
starter switch. Connect the generator field
coil
"F" and armature "A" electrical leads to the
terminals so designated on the installation drawing.
Removethe pipe plug and
install the necessary fittings
for oil dilution at the location indicated on the in-
stallation drawing if the aircraft incorporates an oil
dilution
system.
5-8. INSTRUMENT CONNECTIONS. Apply a film of
grease to the flexible shaftendof the mechanical drive
tachometer, and connect the drive to the tachometer
drive housing. Make sure the flexible shaft conduit
is properly supported and without sharp bends. Con-
nect the oil pressure gauge tube in the location in-
dicated on the installation drawing. Remove the plug
and gasket below the oil cooler and install the oil
temperature gauge capillary with a new gasket. Con-
nect the cylinder head temperature gauge to the
thermocouple previously installed. Connectthe intake
manifold
pressure gauge to the intake manifold riser.
5-9. BLAST TUBE AND BREATHER. To provide the
generator with COOling air, connect the aircraft blast
tube to the connector projecting from the generator
brush access cover. Install the aircraft breather
hose on the crankcase breather and secure it with
hose
clamps.
5-10. FUEL SUPPLY LINE. Connect the fuel line to
a
suitable fitting installed in the 1/4 in. N.P. T. hole of
the carburetor on the level of the manual mixture
control lever.
5-11. AIRCRAFT PARTS. Install whatever engine
baffles are required by the cowling of the aircraft in
such a manner as to form a tight seal between the
upper and lower
compartments so that all cooling air
will be forced to travel through the cylinder fins and
the oil
cooler fins. Attach the overboard drain lines
Install the carburetor air scoop and air filter parts
and the heat valve control. Make sure that the control
will move the valve through
its full range. Complete
the installation
of any other aircraft parts removed
from the engine compartment, and install all parts
of the cowling.
5-12. LUBRICATION. There are no grease fittings or
points to be lubricated other than filling of the oil
sump.
Fill the sump with clean engine lubricating oil
of a reputable
brand and of the viscosity grade rec-
ommended in Table VTI, according to climatic condi-
tion. The choice
of detergent or straight mineral oil
should be
based on operating experience inthe climate
and the conditions of operation anticipated. Detergent
oil
is recommended only if it is used conSistently
from the time the engine is installed, since it will
9

10
NOTE
INSTALL PROP SHAFT WITH DOWEL
HOLES IN LOCATION SHOWN WHEN
NO,I CVL IS ON TOP DEAD CENTER
ON COMPRESSION STROKE
2~DOWEL HOLES
500-.501 DIA
r 6 SOL THOLES
I .501- .503 DIA
~---'5.75 -----\--k=
OIL GAGE ROD
FIELD TERMINAL
\
ARMATU.RE
TERMINAL
~I· , " "
tv
TEMPERATURE 'rir;~ ~ 88
CONNECTION I I
500-14NPTF 11 /
.! I 2.81
EXHAUST n AN~G' "
ACCESSORY DRIVE PAD ----..I A
srD AN020000 TYPE X ~7.l8
DRIVE EXCEPT SPEED =
.8947 X ENGINE SPEED r--- 9.38
MANIFOLD PRESSURE-I
CONNECTION .125-27 NPTF
TEMPERATURE
CONNECTION
.755-.7480IA (TYP)
.4680IA(TVP)
,
2160-24 THREAD
2: TERMINALS
+,-'''jLcd-'-f---\-~--VACUUM PVMP
AETURN
.375-18 NPTF
~"-~~"i'<:""~ OIL PRESSURE
RELIEF VALVE
TACH DRIVE
ASM TYPE I
- BALANCE
TUBE
OIL DILUTION
CONNECTION
.125-27
(ORYSEALl
PLUG-OIL SUMP MANIFOLD DRAIN CONNECTION
.12:5-27 NPTF
DRAIN PLUG
LIFTING EYE
.625 OIA. HOLE
CRANKCASE
BREATHER
CONNECTION
OIL PRESSURE CONNECTION
,125-27 NPTF
FUEL PRIMING CONNECTION
.125- 27 NPTF
-.3125-24NF3
STUD EXT .8BHIGI;
.25701A HOLE
MARVEL CARB.-
MODEL
MA-4-5
Figure 5. Installation Drawing.
STARTER TERMINAL
.375-16 THO
rl2 VOLT STARTER
/ /STARTER AND GENERATOR
/ REMOVAL
CLEARANCE
r-
2. OO
!
MAGNETO
GROUND
TERMINAL
GENERATOR
20AMP
12 VOLT
.Be X1.00 LENGTH
6.41 BLAST TUBE
1
OIL SCREEN REMOVAL
CLEARANCE
FUEL INLET
.250 STO BRIGGS TAPER TAP

loosen and circulate deposits of sludge precipitated
from regular oil previously used in the lubricating
system.
5-13. INITIAL OPERATION. A new or newly over-
hauled engine should be operated with lighter than
normal loads for the first two hours to seat new run-
ning parts and avoid excessive temperatures atpoints
not subj ect to measurement. Running on the ground
should be conducted during the cool
hours of the day
in
warm climates and should be interrupted whenever
oil
or cylinder temperatures approach dangerous
levels. Full throttle operation on the ground should
be limited to very short periods to check performance
and instruments, since the ram effect of flying speed
is necessary for cooling at normal power output or
higher. During the first few hours of operation inspect
all control, wire and tube connections frequently.
All ground operation
must be conducted with the
manual
mixture in the "FULL RICH" position.
5-14. REMOVING ENGINE FROM AIRCRAFT.
Re-
move all engine cowling, baffles, the carburetor air
scoop and other aircraft parts which will interfere
with hoisting of the engine.
5-15. LUBRICATING OIL. Drain the oil sump
as
completely as possible, then replace the drain plug.
NOTE
If the engine is to be shipped or stored, it is
advisable to preserve it as described in Section
IV,
either before removal from the aircraft or
on a test stand where it can be operated with
corrosion-preventive oil and at the recom-
mended temperature.
5-16. TUBE CONNECTIONS. Shut off thefuel supply;
then disconnect thefuel line at the carburetor. Remove
the 1/4-in. square-head pipe plugs atthe bottomof the
front side of the carburetor, and drain the fuel; then
replace the plug. Remove the fitting from the car-
buretor fuel inlet, and replace it with a 1/4-in. pipe
plug. Disconnect the oil
temperature gauge capillary
below the oil
cooler, and replace it with a plug and
gasket. Disconnect the oil
pressure gauge tube,
remove its connector, and replace it with a l/8-in.
pipe plug. Disconnect the intake manifold pressure
gauge line from the manifold riser. Disconnect the
blast tube from the generator. Disconnectthe breather
hose at the engine elbow. If an oil dilution line is in-
stalled, disconnect the tube and replace its connector
fitting with a
1/8-in. plug.
5-17. ELECTRICAL CONNECTIONS. Disconnect the
two
wires from the generator terminals andlabelthem
liA" and "F". Disconnect the two lead wires from the
cylinder thermocouple. Disconnect the
battery power
cable to the
starter switch. Disconnect the grounding
strap from the engine. Immediately after detaching
each wire,
replace the attaching parts.
5-18. CONTROL CONNECTIONS AND DRIVES. Dis-
connect the controls from the tachometer drive,
starter detent control (on GO-300-A, -B and -C
engines), the carburetor-throttle lever, and the
mixture-control lever.
5-19. HOISTING. When all Wires, tubesand other parts
attached to the aircraft have been detached from the
engine and
supported so as not be become entangled
when
it is lifted out, attach a hoist to the engine
lifting eye and take
up all slack without lifting the
engine. Since the engine tends to
assume' a tail-
heavy attitude, loosen the rear mounting bolts first;
then remove the front mount bolts. Hold down on the
propeller mounting flange as necessary while remov-
ing the front mounting bolts. While still holding the
engine in the
same attitude, lift it until it can be
swung to the
horizontal position without striking the
aircraft; then hOist it clear and either roll the air-
craft away, or move the hoist away from it.
5-20. PRECAUTIONS. Do not allow any part of the
engine to touch
the floor. If the engine is to be
overhauled, it should be mounted on the disassembly
stand at once. If it is to be shipped, the preservation
procedure recommended on paragraph 4-11, covering
of
all openings, should be carried out before the engine
is mounted in the shipping crate.
11

SECTION VI
MAINTENANCE INSTRUCTIONS
6-1. DAILY INSPECTION. Beforethefirstflighteach
day a general inspection should be made of engine
control connections and operation,
electrical wire
terminal connections, and for leakage or looseness at
fuel supply, primer and oil dilution tube connections.
The oil
level gauge should be inspected and oil added
if the level is near the "L" mark. After the engine has
been
started and warmed up, the engine instruments
should be observed for possible irregularities in
performance at various speeds from idling up to full
throttle, with the propeller in the low pitch position.
Operation
at full throttle shouldbe limited to the mini-
mum time required to observe oil pressure and to test
the individual ignition systems for excessive drop in
R.P.M. by switching
from "BOTH" to "L"thenback to
"BOTH", then
to "R" then back to "BOTH". Leave the
ignition switch in "L" and "R" positions only long
enough
to stabilize R.P.M. If no drop in speed is ob-
served when operating on either magneto alone, the
switch
circuit should be inspected for loose con-
nections.
6-2. 100-HOUR INSPECTION. At intervals of approx-
imately 100 hours of operating time, it is advisable
to
perform a thorough inspection of the engine in-
stallation to detect incipient troubles due to looseness
of parts and connections, normal wear, fatigue cracks
in visible metal parts and obstructions to air flow.
This inspection should be made
to coinCide with a
routine oil change.
Any instance of improper attach-
ment, leakage, support, fit or operation should be
corrected to assure continued reliable performance
of the engine and its accessories and to prevent
small troubles from becoming dangerous ones, re-
sulting in higher repair costs. The following pOints
should
be given particular attention:
a. Remove all cowling and surrounding baffles nec-
essary to give full access to the engine, accessories
and controls. Clean cowling and baffles to permit
inspection for cracks and looseness of parts.
b. Drain and refill the engine lubricating system, as
described in paragraph 6-3. The engine warm-up
must be carried out before removal of the COWling.
c. Inspect fuel lines, gauge tubes and the breather
tube, connectors and supports, for security of attach-
ment, cracks, and the possibility of tubes touching
electrical wires or rigid members. Tubes are most
likely to crack near end fittings and intermediate
supports. Inspect tube grommets at the fire wall
for
secure installation and close fit.
d. Inspect all control linkages for range of move-
ment, wear at pin jOints, unusual friction or binding,
and
interference with other members.
e. Inspect all hoses and clamps for tightness of
jOints and general appearance. Ascertain that tighten-
ing of hose clamps at the jOints has not deformed in-
take manifold parts so as to cause leakage.
f. Inspect visually all attaching bolts and nuts, plugs
12
and lock wires. If any appear to be loose test it with
a wrench and tighten
as necessary. Usually, oil
leakage
around parts attached to the crankcase will
precede other evidence of looseness and should be
corrected by tightening of the attaching parts unless
the extent
of leakage indicates that a gasket or oil
seal should be replaced. Especially at the first
periOdic inspection after installation of a new or
rebuilt engine, it is advisable to test tightness of base attaching
nuts with a wrench.
g. Shut off the fuel supply to the carburetor. Dis-
connect the fuel supply line at the carburetor. Remove
and clean the fuel
strainer; then replace it, and recon-
nect the supply line.
h. Remove, clean,
inspect and measure gaps of all
spark plugs. (Refer to Table n.) Replace any plug
with a damaged
insulator, loose or badly eroded
electrode or damaged thread. Before replacing a
plug, make sure that its gasket is smooth. Beforereconnecting
cables to the
spark plugs, inspect the terminal elbows, springs
and sleeves for damage. Inspect all cables for breaks or
ruptures in
the insulation and for secure attachment to the
magneto outlet plate.
i. If there was any sluggishness inthe engine operation
which was not
traced to thefuel or induction system or
to the spark plugs, the breaker covers may be removed
for inspection
of pOint gap and condition. Ordinarily
it is not necessary to check ignition timing; however,
wear of the magneto breaker cam follower can result
from lack of lubrication andmake the timing late. For
corrective procedure refer to paragraphs 6-9, 6-10
and 6-11.
j. Remove all valve rocker covers and inspect valve
stems, springs, retainers, keys and rockers for evi-
dence of inadequate lubrication and breakage. All
parts should be covered with oil. If there is any
lash in any valve train when the valve is fully
closed, the hydraulic tappet
is not operating properly.
For removal procedure refer to paragraph 6-18.
Use new gaskets and lock washers when replacing rocker
covers.
k. Inspect cylinder fins for possible obstructions.
Make
sure that intercylinder baffles are securely
attached and held in contact with the cylinders.
1. Remove, clean and replace the carburetor air
cleaner according to the aircraft manufacturer's in-
structions.
m. Inspect the oil cooler fins for obstructions, and
blowout any dirt with compressed air or flush with
cleaning solvent.
n.
Test engine mount bolt and retighten to specified
torque if found loose.
o. It is advisable to wipe any oil or caked dirt from