NT-MDT Solver SNOM User manual

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INTRODUCTION
This manual is designed to give servicemen an indepth service procedure
for the Convertible 7.6 tractor, and as an aid in diagnosis and repair.
This manual cannot take the place of proper routine maintenance, care
and adjustments.
Gravely resenles the right to change speciffcations, or design at any time
without notice or incurring obligation.
LH means Left Hand.
RH means Right Hand.
Directions afe given from the operators position; that is, as you would
stand behind the tractor.
AGRA/ELY
One Gravely Lane
Glemmons, North Carolina 27012
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TABTE OF CONTENTS
Trouble $trooting ('Esgine)
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::i1 .,,... . ._ j,
Air Intake Systert
Lubricatim
Fuel Sy*m
El@tricat Syst€m
Govemor
Cleeoing
Engine Tests
Engine-Ceneral Service .
Fan
Engine Reconditioning
Cylinder Reconditioning
Transmission Trouble AnalYsis
Forward-Rwerse
Higb-Low- :i' ',r '':-:; :'-. -.:':i ,:: i:' i-
. ,'",4*; - ., ...*:=' "+ '".; : '
Dtrerentiirl p.Sp€bd)
Differentisl (Std)
PTO
Starter Clutch
4
8
5
0
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:.9
10
r0
','1 .1l
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t2
18
l9
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22
2A
26
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SAFETY PROCEDURES
IT IS TOO LATE TO NEMEMBER WHAT SHOULD HAVE BEEN DONE
AFTER THE ACCIDENT HAS HAPPENED.
Many hours of lost time and much sufiering can be caused by the failure
to practice simple safety rules.
l. Make sure the work area is clear of obiects that might be picked up and
thrown.
2, Do not wear loose fftting clothing that might get caught in moving parts.
3. Disengage all clutches prior to sti*ing the engine.
4. Do not add fuel to the tractor when it is hot, while it is running, or while
you are smoking.
5. Never run the engine in a closed garage or shed without adequate ventilation.
6. Do not try to oil or grease the tractor or its attachments while in operation.
7, Adequate ventilation must be provided when batteries are being recharged.
In addition, sparks, open fames and smoking should be avoided since
hydrogen gas is produced which, if ignited, can cause internal explosion
that can shatter the battery. This gas is produced in quantity only while
the battery receives high rate of charge but can linger for several hours in
a poorly ventilated area.

CONDITION POSSIBLE CAUSE
A, Hard Sta*ing or Loss ol Pooer
Check for dirty air cleaner frst. 1. Faulg lgnition.
a. Loose or grounded high tension or breaker point
leads.
b. Improper breaker point gap and timing.
c, Defective breaker points,
d. Faulty spark plug or improper gap.
a. Faulty condenser or coil.
2. Faulty Fuel System.
a, Gasoline not getting to carburetor.
Dirt or gum in fuel line.
b. Dirt in carburetor.
c. Carburetor improperly adjusted.
B. Ooerheating 1. Insufficient available cool air.
2, Dirty air intake, shroud or cooling ftns.
3. Improper fuel.
4. Fuel mixture too lean.
5. Improper ignition timing.
6. Engine overloaded.
r 7. Tight tappet clearance.
C. Backfirtng t.
2.
3.
Fuel mixture too lean.
Improper .timing.
Valve "stickingr'.
D. Occasional "SHp" at Htgh Speeil l. Spark plug gap too wide.
2, Improper carburetor setting or lack of fuel'
3. Wrong type spark plug. Use recommended spark
plug'
4, Improper timing.
E, Operating Enatlcallv l. Clogged fuel line.
2. Water in fuel.
3. Faulty choke control
4. Improper fuel mixture.
5, Loose ignition connections.
6, Air leaks in manifold or carburetor ctnnections,
7. Vent in gas cap plugged.
F. Engine WilI Not ldlc l. lmproper carburetor idling adjustment.
2. Carburetor clogged.
3. Spark plug gap set too close.
4. Leaking carburetor or manifold gaskets.
TROUBTE SHOOTING
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AIR INTAKE SYSTEM
AIR CLEANER
COVER CLEANER
ELETEI{T
oDeratinq with a cloeged element causes a richer fuel
nii*ture "wtrictr can biE to formation of harmful sludge
deoosits. Alwavs cover carburetor or air horn when air
cblaner is rembved for servicing.
Drv tvoe air cleaner elements should be sendced
onb fiheti required. Need for air cleaner service is
evident by a suiiden loss of power for no apparent reason.
To cl6an, remove elem6nt and tap lightly on a fat
surface to remove loose surface dirt, Replace element if
dirt does not drop ofi easily or if the element is damaged
in any way. Akb, replac6 element if there is any 6vi-
dence of dirt on the inside surface of the element.
DO NOT wash dry elements in any liquid or attempt
to blow dirt ofi with'air hose as this will puneture tEe
fflter element.
SEALING
WASHER
WING NUT
FLAT WASHE
CLEANER
MOUNTING BRACKET
AIR CLEANER
MOUNTING BASE
Handle new element carefully - do not use if the
ket surfaces are bent. twisted or damaged in anygasket surfaces are bent, or damaged in any
ments. Use of other
way. Use only genuine Gravely elements. Use
elements will void warranW. Not onlv must tb eleiaents will void warranty. Not only must the proper
element be used but it must be properly installed to
The importance of maintaining an air cleaner in
DroDer condition cannot be over-emohasizedl Dirt in-
lu&a through improperly installed, ifrproperly serviced
or inadequate dry file elements, wears out more en-
gines than does long hours of operation. Furthermore,
elements wrll vorct warranty. Not only must tne proper
element be used but it must be properly installed to
prevent unffltered air from entering the engine.
Install the air cleaner assembly in this sequence on
the air cleaner mounting bracket:
l. Rubber gasket 5. Rubber sealing
2. Air cleaner mounting base washer
3. Element 6. Flatwasher
4. Air cleaner cover 7. Wing Nut
Be sure tbe element gasket surfaces fft tightly on the
base and cover. The wing nut should be ffnger tight.
LUBRICATION
_ _ Oil capacity is 5 U. S. pints. Use API ciassification
SC or SD oils.
Summer-SAE 30 or SAE 10W 30.
Winter - (32' F or below) SAE 10W or SAE lOW 30.
Maintain at oil level at full mark on dipstick. Be sure
tractor is level when checking oil.
Oil Changes
Change the oil after the initial eight hours of opera-
tion. Then change the oil every 40 hours under normal
conditions, oftener under dusty conditions and/or periods
of extended operation.
Drain oil by removing the oil drain plug, the bottom
bolt on the L. H. axle housing.
Be sure oil drain washer is in place when replacing
the bolt.
Oil Fllter
Under normal conditions, change the oil fflter every
80 hours, however, under extremely dusty conditions
and/or extended operation under heavy load, change
the oil fflter every 40 hours.
llhe oil fflter must be installed bv hand. Install the
fflter following the lnstructions printrid on the fflter.
Periodic oiling of all'linkage pivot points aids oper-
ation.
Figure I

FUEI SYSTEM
CARBURETOR
RUABER WASHER
AIR JET ADJUSTMEI{T VALVE fUEL SUPPI-Y SYSIEM
IHROTTT€PTATT
(ldlc Pos;tion)
I AO.JUSTMET{T VALVE Figure 3
Figure 2
A. Adjustment
l. Screw the main jet adjustment needle (a brass
T-needle) in until it is snug. Do not foroe or scrbw it
Ughtlv.
2. Back ofi the main jet adjustment needle 114 turns.
3. Start the engine and open the throttle halfivay.
After the engine warms up, begin screwing the needle,
slowly. As soon as the engine begins to slow down, stop
and back the needle ofi until the engine picks up {peed.
4. Screw the idle air jet adjustment needle all the
way in; then back ofi one turn. Start the engine and
allow it to idle. Screw the needle in until the engine
begins to run rough. Then back the needle ofi until
engine runs smooth.
FUEL SUPPLY SYSTEM
(See Figure 3)
The fuel supply system is made up of the threaded
fuel inlet, the fuel valve seat, fuel valve needle, foat and
fuel bowl.
The fuel supply line is connected to the threaded
inlet. The fuel travels through the fuel valve seat and
Dasses around the fuel valve and into the fuel bowl. The
fevel of the fuel in the fuel chamber is regulated by the
foat through it control of the fuel valve. The fuel valve
does not open and close altemately but assumes an open-
ing, regulated by the float, suficient to maintain a proper
level in the fuel chamber equal to the demand of the
engine according to its speed and load.
The inside bowl vent as illustrated by the passage
originating in the air intake and continuing through to
the fuel bowl, is a method of venting the fuel bowl to
maintain proper air fuel mixtures even though the air
cleaner may become restricted. This balancing is fre-
quently referred to as an "inside bowl vent".
IDLE SYSTEM
(See Figure 4)
The idle system consists of two idle discharge holes,
idle air passage, idle adiusting needle, idle jet and fuel
pick-up passage.
The fuel for idle is supplied through the main iet
to a well directly below the main discharge jet. The
oick-uo Dassaqe is connected to this well bv a restricted
tttitti"g it the" bottom of this passage. Th6 fuel travels
r:'g,*-:."J----il
Figure 4
through this channel to the idle jet calibration. The air
for thi idle mixture originates back of (or from behind)
the main venturi. The position of the idle adjusting
needle (normally one turn from its se,at) in this passage
controls' the suciion of the idle jet and thereby idle, mix-
ture. Turning the needle in closer to its seat results in
a greater suciion with a smaller amount of air and there-
foie a richer mixture. Turning the needle out away from
its seat increases the amount bf air and reduces the suc-
tion, and a leaner mixture is delivered. The fuel is
atomized and mixed with the air in the passage leading
to the discharge holes and enters the air stream at this
point.
HIGH SPEED SYSTBM
(See Figure 5)
The high speed system controls the fuel mixture at
part throtfle speeds and a wide open throttle. This
iystem consists'of a venturi, control'ling the maximum
volume of air admitted into the engine; the main iet,
which regulates the flow of fuel from the float chamber
to the ma'in discharge jet; the well vent, which maintains -J
uniform mixture ratio under changinq suction and engine
speeds; and a main discharge iet, which delivers the fuel
into the air stream.
The main jet controls the fuel delivery during the
E DISCdARG€HOTTS
IOLE AOJU
NITDLI
- IDTE AIR
(f ron Lehin,.l V€nturi)
tDLt Ftf,t
PICX.UP PASSACE
MAIN JEI .
ADJU'MENt

:j'"og "t'-'",fC
Figure 6
part throttle range from about one-quarter to full throttle
opening. A main jet adiustment permits a limited con-
trol of the main jit fuei. Oridinirily an adjustment of
l7z tums from its seat will give proper tiri*ture. To
maintain a proper mixture ration a Cmall amount of air
is admitted through the well vent into the discharge iet
through _the air bleed holes in the discharge iet at a
point below the level of fuel in the metering w6ll.
CHOKE SYSTEM
(See Figure 6)
At high speeds the fuel flows from the fuel chamber
through the main jet and into the main discharge iet
where it is mixed with air admitted by the well-vent,
and the air-fuel mixture is then dischaiged into the air
stream of the carburetor.
The choke system consists of a valve mounted on
a shaft located in the air entrance and operated extern-
ally by a lever mounted on the shaft. The choke valve
is used to restrict the air entering the carburetor. This
increases the suction on the jets when starting the engine.
The choke valve is of a "Semi-Automatii' type, having
a pgppgt valve incorporated in its design, which is con--
trolled by a spring. -
- The foppet u"iu" op"n, automatically when the en-
3ine s-tarts and admits air to avoid over-choking or food-
ing of the engine. The mixture required for itarting is
considerably richer than that needeld to develop power
at normal temperatures. As the engine ffres and speed
and suction are increased, the mixture ratio must be
ra-pidly reduced. This change is_ a-ccomplished through
adjustment of the choke valve and the auiomatic openiis
9f the poppet valve to admit more air when the ^enginE
fires.
SEPARATE CARBURETOR BODIES
(a) lemove the four assembly screws using a screw-
driver.
(b) Separate the throttle body from the fuel bowl as-
sembly.
DISASSEMBLE THROTTLB BODY
(a) Remove float axle as follows:
(1) Press screwdriven against float axle at slotted
side of float hinge bracket and force through
hinge bracket.
(2) Remove float axlg completely with ffngers from
opposite side and remove foat.
(b) Remove fuel valve needle.
(c) Remove the assembly gasket.
(d) Remove the fuel lr"iu"" seat and fibre washer.
(e-) Remove the idle jet using a small screwdriver.
(f) Remove the idle adjusting needle and friction spring.
DISASSEMBLE FUEL BOWL BODY
(a) Bgmove the main jet adiusting needle assembly and
ffbre washer using-a Vzo wreich.
(b) Rem_ove the draii plug (hex) from bottom of fuel
bowl.
(c) Remove main jet and ffbre washer.
(d) Remove main discharge jet and ffbre washer from
center of large opening in machined surface of the
fuel bowl.
(e) Remove well vent jet lrom center of large opening
in machined surface of the fuel bowl with f, smal-i
screwdriver.
CLEANING PARTS
(a) 9lean all _metal parts. thoroughly with cleaning so-
Iution and rinse in solvent.
(b) Blow out all passages in the air intake and fuel
bowl casting and thiottle body.
(c) NOTE: Be sure all carbon diposits have been re-
moved from throttle bore and ldle discharge holes.
It is advisable to reverse fow of compressed air in
all passages to insure that all dirt has bten removed.
Never use a wire or drill to clean out jets.
INSPECTION OF PARTS
(a) Flo_at Assembly. Replace foat assembly if loaded
with gasoline, damaged, or if foat axle bearing is
wom excessively. Inspect top side of foat leveifor
wear where it contacts fuel valve needle.
NOTE: Such wear can affect the foat level.
(b) Float A_xle. Replace if any wear can be visually
detected on the bearing surface.
(c) F_uel Valve Siat and Needle Assembly. Always re-
place fuel valve seat and needle because both-parts
wear and may cause improper foat level.
(d) Idling Adjustrirent Needl6 "r,id Spting. Inspect point
of needle. This mtrst be smooth and free-of ri-dges.
(e) Gasket-s. Replace all gaskets and ffbre washers eviry
time the carburetor is disassembled.
REASSEMBLY
FUEL BOWL BODY
(a) Install main discharge jet and ffbre washer in fuel
bowl and tighten ffrmly.
(b) Install well vent jet in fuel bowl and tighten with
a small screwdriver.
MAIN JET
AOJUSTMENI
iHrGH SPETD SYST€Mi
Figure 5

(c) Install main jet and ffbre washer.
(d) Install the drain plug (hex) in threaded passage bot-
tom of fuel bowl.
(e) Install main jet adiustment seat lightly and hcek out
l/z turns.
Figure 7
THROTTLE BODY
(a) Install idle adjusting needle and friction spring in
threaded passage on side of throttle body. Seat
lightly with screwdriver and back out one full turn.
(b) Install idle jet.
(c) Install fuel valve seat and ffbre washer.
(d) Install fuel valve needle in seat followed by foat
and float axle.
SEE FIGURE 7. The 'A- dimension shoulcl be f 5Al a
inch plus or minus 3/64 inch.
(e) Float Level. Check position of foat assembly for
correct measurement to obtain proper float level
using depth gauge.
NOTE: Do not bend, twist or apply pressure on &e
foat bodies.
f (1) With bowl cover assembly in an inverted posi-
tion, viewed from free end of foat, the foat must
be centered and at right angles to the machined
surfaces. The foat setting is measured from the /
machined surfaces (no gasket) of cover to top t
side of the foat bodies at highest point. l
(2) Bending Float Lever. To inireasd or decrease t
distance between foat body and machined sur- l
face use long-nosed pliers and bend lever close
to foat body.
NOTE: Replace with new float if position is ofi
more than l/16 inch.
ASSEMBLE CARBURETOR BODIES
(a) Assemble the two completed bodies and four screws
and tighten screws evenly and ffrmly.
(b) Hold the throttle lever in a closed position and
tum the throttle stop screw in until it iust contacts
the stop on body, then tum screw in 172 additional
turns.
ETECTRICAT SYSTEM
Spark Plug - Champion H-8 Gap - .025 inch
Timing
l. Remove cylinder head and gasket.
2. Loosen magneto coupling bolt until coupling will
slip on the camshaft extension.
3. Bring the piston to top dead center on compression
stroke (both valves closed).
4. Back piston down cylinder approximately one inch
by tuming starter pulley counterclockwise.
5. Measure accuratelg 3/8 inch from top of cylinder and
bring piston up to this point.
6. Align the timing marks (straight marks) on magneto.
7. Reassemble the magneto coupling using .015 feeler
gauge between the ffbre block and the coupling
fange before tightening bolt so as not to clamp the
impulse.
8. Reinstall head and gaskets torquing to 20 ft. lbs.
LUBRICATION
The only lubricating point in the magneto is the cam
wiper felt. This felt, which lubricates the breaker arm
at point of contact with the cam, should be lubricated
with 2-3 drops oil whenever it is necesSary to replace
the breaker contacts.
IMPORTANT
Incorrectly adiusted spark plug gaps cause magneto
failure more frequently than any other condition.
Spark plugs should be inspected at frequent inter-
vals, the size of the gap should be carefully checked and
adjusted and the plugs thoroughly cleaned.
All oil, grease, and dirt should frequently be wiped
ofi the magneto, lead wires, and spark plug insulators.
Figure 8
Keeping these parts clean and the spark plugs properly
adjusted will improve the engine performance and at
the same time will prolong the life of the magneto.
wrco
MAGNETO FACE PLATE
FAIRBANKS.MORSE
MAGNETO FAGE PLATE
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Figure 9
MAGNETO COVER
The magneto cover, can be removed by loosening
the four screws which hold. it in place. When replacing
the cover be sure that the cover gasket is in its proper
place.
ftnnneKER coNTACTS - REpLACEMENT AND
ADJUSTMBNT
The breaker contacts should be adiusted to .015"
when fully opened. To adjust the contacts, loosen the
two clamp screws enough so that the contact plate can
be moved.
Insert the end of a small screw driver in the adjust-
ing slot and open or close the contacts by moving the
plate until the opening is .015", measuring with a feeler
gauge of that thichress, tighten the two clamp screws.
" fo replace the contacts reniove the bieaker, the
spring clarnp screw, the breaker arm lock and wisher,
and fhen lifl the breaker arm from its pivot. Remove
the spacing washer and the two breaker plate clamp
screws. The breaker plate can then be removed.
If the contacts need replacing it is recommended
that both the ffxed contact and the breaker arm be re-
placed at the same time, using replacement breaker set.
- After assembly the contacts should be adiusted as
described above. The contacts should be kept clean at
all times. Lacquer thinner is an ideal cleaner for this
purpose.
CONDENSER
To remove the condenser, ffrst disconnect the con-
denser lead by removing the breaker arm spring screw,
then remove the two condenser clamp screws, and the
condenser clamp. When replacing the condenser make
sure it is properly placed and that the clamp screws are
securely tightened.
COIL AND COIL CORE
The coil and coil core must be removed from the
magneto housing as a unit. Disconnect the primary wire
from the breaker arm spring terminal by removing
screw, take out the two coil core clamp screws, and
remove the clamps. The coil and core can then be
pulled from the housing. When replacing this group
make sure that the bare primary wire is connected under
the core clamp screw and that the insulated wire is con-
nected to the breaker arm spring terminal.
REMOVAL OF COIL FROM CORE
The coil is held tight on the core by two wedges. It
will be necessarv to-press against the coil core with
considerable force to rtmove lt from the coil. The coil
should be supoorted in such a way that there is no
danger of the irimary of the coil b6ing pushed out of
the secondarv.
When replacing the coil on the coil core, slide it on
then press in the two coil wedges, one on each end,
until lhey are fush with the primary of the cpil.
2.
3.
4.
D.
6.
7.
8.
9.
GOVERNOR
Governor service is indicated when the governor is
not functioning properly under load.
Two govemor repair kits are available. If the com-
ponents of these kits cannot repair the govemor, it will
be necessary to replace the governor.
1. Main shaft assembly kit consists of:
Retainer
Bearing
Main Shaft Assembly
2. Seal repair kit consists of:
Oil Seal
Oil Seal
Gasket
GOVERNOR OVERHAUL PROCEDURE. Remore
the govemor from the tractor, and proceed as followb:
1. Remove two screws and separate cover assembly
from body assembly.
Remove retainer and thrust sleeve from cover and
main shaft assembly.
Remove two flyweight pivot pin retainers and care-
fully tap out flyweight pivot pins using a 1/8 di-
ameter punch, and tapping against the grooved end
end of the pivot pin.
Remove two screws and rocker lever from body
assemblv.
Slip oui shaft and lever assembly from body as-
sembly.
Clean all parts carefully in a suitable solvent, to
removed all grease, dirt and foreign material.
Inspect all parts carefully for wear, cracks or dam-
agd and reila"" parts as necessary. A main shaft
assembly kit and leal repair kit are available. Re-
place the governor if the parts in these kits can-
not repair the governor.
Inspect for excessive wear on main shaft, pivot
pini, thrust sleeve and cross shaft & lever. Replace
as necessary.
Inspect for excessive wear on main bearing and
rear bearing and cross shaft bearings in body. Re-
place body as a unit if bearings are wom or dam-
aged.
Replace spring if it is damaged or if loss of tension
is apparent.
10.

11. Replace seals if damaged or worn.
L2, Relassemble the goverior in the reverse order of
disassembly.
IMPORTANT: Pack the internal component parts, espec-
ially the bearings, pins, shafts and all rotating and slid-
ing parts, with"luEricant. A total of 3 oundes of this
lubricant is to be packed within the governor housing, in
order to supply maintenance-free operation of the gov-
emor.
CLEANING
A clean tractor is much easier to work on than a dirty
one. Also, dirt will be prevented from entering the
tractor. After being repaired it will look better and
onerate cooler.
' On extremely dirty tractors, it may be necessary to
raise the fuel tink aird fan housing assembly to clean
the tractor thoroughly.
CAUTION: Before steam cleaning a tractor, remove
the magneto. Use care in cleaning around the carbu-
retor, do not direct the steam or water into the air
cleaner. After cleaning replace the air cleaner element.
ENGINE TESTS
Oil Prcssure; At full throttle (260G2800 rpm), the
hand on the oil pressure gauge should be approximately
3/q of the way over the normal range.
Low oil pressure is a possible indication of a serious
problem. However, before teardown, check the follow-
ingt
{
I
CHASS IS OIL PUMP
ENG I NE FI LTER
PRESSURE
RELIEF
VALVE
PROBLEM NEMEDY
Low oil level Check level, add oil as required.
Low rpm Adjust to 260G2800 rpm'at full throtde.
Low relief valve setting Adjust relief valve setting, with adequate pressure,
a heavy stream should still be visible through the oil
ftllor nenlr
Lose of pump suction due to air leak - usually evi-
dent by oil leak. Check fittings for tightness. Torque pump cap bolts
to 80 in. lbs.
Conrytessiort: The results of a compression test can
be used to check the condition of an engine. High
compression lsxdings, 70-80 psi, indicates the engine is
in good operating conditions.
LOW COMPRESSION
POSSIBLE CAUSE REMEDY
A. Cylinder head gasket blown due to cylinder head
warped or loose.
B. Piston rings worn - blowby occurring.
C. Valves leaking.
A. Remove head, check for flatness. Reinstall with new
gasket and secure in proper sequence to specifted
torque valve.
B. Recondition cylinder, see page 12
C. Recondition cylinder, see page 12
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Higher than normal compression can indicate that
excessive carbon deposits have built up in the com-
bustion chamber.
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COOLING
If tractor is getting hot, check for blockage of the
cooling system. Air is blown around the cylinder and
across the cylinder head by the fan. The fan housing
and the cooline ftns on the cvlinder and cvlinder heai
must be kept clean and unobitructed at all'times.
NEVER OPERATE WITHOUT FAN OR FANBELT
OR WITH ANY AIR DEFLECTOR OFF. The air de-
fector directs air fow around the cooling ftns. Removal
results in improper air circulation.
Improper timing can cause tractor to nxr hot-
ENGINE GENERAT SERVICE
ENGINE RECONDITIONING
EXTERNAL SURFACES
External surfaces (tractor as well as engine) must be
maintained in a clean condition, free of any dirt or oil
accumulation which reduces cooling eftciency.
FAN
Ihe fan shaft is supported by two bearings with a
spacer between them. -The bearing housing is packed
riith general purpose grease upon issembly.
Whenever a tractor is overhauled the bearing housing
shoqld be repacked with grease. Be sure the ipacer ii
in place between the bearing.
I
ENGINE REMOVAL
l. Remove a_ny attachment from tractor and replace
with attachment cover plate. Tip tractor forwaid on
advance casting.
2. Disconnect throttle and choke controls from car-
buretor.
3, Turn ofr fuel and remove fuel line from carburetor.
4. Remove the air cleaner assemblv. Remove air
cleaner hose from carburetor and'the air cleaner
mounting bracket.
5. Disconnect governor linkage, if so equipped.
6. Remove the-1,.H. air defeitor
7. Remove fan belt.
8. Remove the bolt securing the High-Low and
Forward-Reverse controls at R.H. handle.
L On swiftamatic tractors, disconnect the shifter rod
from the shifter handle on the R.H. Handle.
10. Disconnect kill wire from magneto.
11. Remove R.H. air defector.
12. Remove cylinder air defector.
13. Remove nuts and lockwashers from fan housing
bracket weldments.
14. Loosen bolts securing rear hitch to transmission and
bolts securing hitch braces to hitch. Remove hitch
braces from fan housing brackets and lower hitch
to foor.
15. Loosen bolts securing handles to the fan housing
and bolts securing handles to transmission.
Figure 12
16. Pull out bottom of fan housing to clean fan housing
brackets and raise handle, fan housing, and fuel
tank assembly up over engine and out of way.
I7. Remove oil lines from each side of oil pump and
from elbow on L.H. side of engine crankcases.
f8. Remove the nut and washer from the stud extend-
ing through the chassis casting in front of the
engine.
19. Loosen the magneto coupling.
20. Remove the bolts securing the engine to the chassis.
2L. Slide engine back and away from the ehassis.
ll
Figure 1l

CYIINDER
CYLINDER REMOVAL
1. Expose engine (Step l-16 Engine Removal)
Fig. 13
Remove cylinder head and
Loosen the nuts securing
crankcase.
RECONDITIONING
4. Remove the four nuts and washers
cylinder to the crankcase. securing the-
I
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gasket.
the valve
2.
3.
RECONDITIONING
A. Gasket surfaces
Check all surfaces to be sure that they are free of
all gasket fragments and sealer materials. Surfaces must
be free of scratches or nicks.
B. Cylinder Bore
Diameter of standard cylinder is 3.2545 - 3.2535.
Measure the cylinder bore at two points 90' apart at the
top and bottom of the wear pattern to determine wear.
Figure 14
5. Lift the cylinder up ofr the crankcase and piston.
Figure 15
guides to the
Bore Diameter
3.2il5/3.2535
3.2585/3.2595
3.263513.2645
3.2685/3.2695
3.273513.2745
3.278513.27%
3.2835/3.2845
Piston Size
std.
.005 oversize
.010 oversize
.015 oversize
.020 oversize
.025 oversize
.030 oversize
Ring Size
Std.
.0O5 oversize
.010 oversize
.015 oversize
.020 oversize
.025 oversize
.030 oversize
{
I
12

VALVES
ADIUSTMENT
Cold - intake .015
exhaust .015
VALVE REMOVAL
-, .Remove cylinder from engine. See Cylinder Recon
ditioning steps l-5.
Figure 16
Re_lease the valve spring compressor, and remove
ffiT;;r:n*8 cap, valve spring and valve spring
Remove valve from cylinder.
Repeat steps 3, 4, and'5 for other valve
sEAr wlprH #"*
6$'rrrex.
5.
6.
F
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BLACK AREA
sHows ExcEss
REMOVED
Figure 17
Grind rialve seats at an angle of. 45". Be sure the
seat is square with the valve guide bore. Crind
seats to a dimension of 3/64 to 5/64. If the valve
seat exceeds 5/M on one side, use a 60' valve seat
reamer to remove the excrss valve seat width.
t.
1. Support the cylinder in a vise.
2. Remove carburetor from the intake manifold.
3. Using a valve spring compressor, compress the valve
spring and remove the valve spring key.
l3

Pistons and rings are available in standard, .005; .010;
.015; .020; .025 and ,030 oversize. Be sure to use the cor-
rect rings with the correct pistons. Also, be sure the pis-
ton-s-and rings are correct for the rebored cylinder. -
Never reuse old rings,
A _new-piston pin should.be used with a new piston
or rod. Always use new retainers even though yoi may
be using the iame piston and pin.
Pistqrn is equipped with three rings.
I Chrome Compression Ring
(Rin-g Gap: .bte to .090)"
I Steel Compression Ring
(Ring Gap: .008to .016)
I Oil Scraper Ring
Three Piece Chrome Oil
Ring: Ring (Gap .015 to .055)
The three-piece oil ring, should have from .015 to
.055 end gap for the two flat segments. The top chrome
compression ring should have .012 to .020 end gap.
Measure the end gap with a fceler gauge, with -tlie
ring removed from the piston and held in the cylinder
bore.
Piston skirt clearance is .0039.005. Measu'e with a feel-
er gauge at right angles to piston pin.
FLYWHEET
1. After removal of the cylinder, remove the valve
guide - valve plunger assemblies from the crank-
case.
2. Remove the fan drive pulley and woodrufi key
from the timing pinion shaft. Remove the set screw
from the drive pinion bearing.
3. Remove the bolts holding the fan housing brackets
to the crankcase.
4. Carefully polish the magneto shaft extension to re-
move all rust and paint.
5. Pry th" crankcase halves apart, remove the fywheel
assembly.
6. Remove the spreader bolt and nut.
7. Remove one fywheel using a two jawed gear puller
or press.
8. Remove rod from crankpin and press the crank-
pin out of the other fywheel.
Carefully examine all parts for abnormal wear or
damage. Check for damage also on the timing pinion
shaft and the drive pinion shaft in the flvwheels.
If a new rod is uied, a crankpin must be used. If a
new crankpin is used, a new rod must be used.
a. Crankpin diameter is I,497-1.498"
9. The grooved end of the crankpin is to be installed
in the flvwheel with the drive oinion shaft. Alisn
the oil hble of the flywheel as irear as possible "to
the hole in the groov6 of crankpin. Press^the crank-
pin into the flywheel. The flywheel-must be pressed
tightly to the shoulder on the crankpin.
10. Place connecting rod on crankpin.
ll. Align the flywh_eels as,close as possible and press
the remaining flywheel on the -crankpin.
12. Install a neu spreader bolt, washer and nut. Torque
to 45 ft. lbs. Stake nut. 14
PISTON - RINGS
ASSEMBLY
Fig. 18
Fig. 19

Fig. 2l
13. Support- end" of timing pinion shaft and drive
pinion shaft between two centerins soindles. Usins
i aial indicator check run out "an& bahnce flyl
wheels to within .005 TIR.
b. Oil Pumo:
Oil pumir bushing - .4373-.4388
Master qear shaft - .4363-.4368
Oil pump cap lfaOZSfl) has no gaskets. Use of Loctite
Ito. 68 plastic gasket is recommended. After application,
the Loctite must cure for 12 hours. Do not run engine
until after curing.
l
}
l5

CAMSHAFTS
CRANKCASE
With the rod at top dead center install the rod-
fvwheel assemblv in the outer crankcase. tlse care
obt to move the'camshafts out of time.
Liberally apply Permatex ff3 to the edges of the
crankcase.
Remove the oil seals and expansion plug from the
inner crankcase and place crankcase over camshafts
and drive pinion shaft.
If not previously removed, remove the allen screw
from th1 end of the drive pinion shaft.
Using the special Gravely erankcase Assembly Pul-
ler, "assembie the crank'case together. Instail the
setscrew in the inner crankcase against the drive
CAMSHAFT
To insure proper engine operation, accurate timine l
of the camshafts is necessary.
.Each camshaft gear will have one timing mark on it
and the idle gear has three ring marks on it.
Line up the mark on each camshaft gear with a
timing maik on the idle gear. The other irark should
be centered between the camshafts.
ASSEMBLY
pinion bearing.
Unscrew the Crankcase Puller from the drive pinion
shaft and reinstall allen screw in end of drive pinion
shaft.
Install the fan housing brackets with the top bolts.
Check end play of the timing pinion bearing,-
should be .0i0-.b20. If end plav is in excess of this
amount, remove the bearini dnd pump body and
install shims.
Using the oil seal protector and driver install new
oil seals on the camshafts. Install new expansion
plug.
I
I
Fig.22
o
3.
4.
5.
8.
I
{
l6

ENGINE ASSEMBTY
1. Install the valve guide and plunger assemblies on
each __side of the crankcase, do not tighten.
' 2. Install a new gasket to the four studs on the crank-
case.
3. Suppor! the piston assembly and start the cylinder
assembly down over the piston and rings.
Figure 24
Guide the cylinder down over the piston guiding
the valves and springs into the valve guides and
the cylinder over the studs of the crankcase.
Secure the cylinder to the crankcase, tighten the
valve guide assembly nuts.
6. Adjust the valve tappet clearance .015 inch;
intake .015 inch exhaust.
Fig. 25
Install head using new gasket. Torque bolts to
20 ft. lbs.
Install cylinder air defectors.
F
F
4.
5.
Figure 23
l.
2.
3.
4.
5.
6.
7.
8.
t9.
. 10.
F tt.
L2. trols to the R.H. handle.
13. Install fan belt.
14. Install LH air defector.
f5. Install carburetor on intake manifold.
16. Install air cleaner hose on carburetor and air
cleaner mounting bracket.
,--'.17, Attach fuel line to carburetor and turn on fuel.
t 18. Connect throttle and choke controls to carburetor.
19. Time engine according to instructions on page 8
n.
21.
ENGINE INSTATIATION
Slide engine in position on chassis.
Install six bolts securing the engine to chassis.
Install the washer and nut on the stud extending
through the chassis casting in front of the engine.
Attach the intake and discharge lines to the oil
pump. Connect the line to the side of the engine.
Lower handles, fuel tank and fan housing down
over engine.
Position fan housing on studs of fan housing
brackets.
Raise hitch and install hitch braces on fan housing
bracket studs.
Install loclaarashers and nuts on fan housing bracket
studs.
Install R.H. air defector.
Install magneto kill wire.
On swiftamatic tractors, connect the shifter rod to
the shifter handle at the R.H. handle.
Attach the High-Low and Forward-Reverse con-
l7

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FORWARD. REVERSE
Figure 26
Figure 27
To gain access to the Forward-Reverse planetary, re-
move the attachment or attachment cover plate, PTO
mechanism and the advance casting.
Rotate the actuating lever and release the planetary
rystem. Carefully examine all parts for wear, excessive
nlav or damaqe.
' 'Before disissembling the planetary, check the fft of
the gears on the pins. If geals appear too tight or too
loose, disassemble the planetary and check the gears
and pins for wear. (NOTE: Bolts have left hand threads)
Asseinbly and time the planetary as follows:
- l. Place the sun pinion in the bore of the front pin
olate.
2. S"c.t." the pin plate quill, over the sun pinion, to the
pin plate with 3-XxX bolts.
3. Pla& orbit gear bushing in gears. Do not use old
bushing in nlw gears oinew-bushing in old gears.
Figure 28
4, Mesh the three gears with the sun pinion so that the
timing marla (piunch mark on ea6h gear) from an
equal-sided triangle.
5. Se-cure the revers-e idlers to the front pin spacer. .
6. Secure the front pin spacer to the front pin plate
usine the snecial bolts.
Wheil replfcing this unit in the transmission, mesh
the teeth of the acutating rod and clutch slide rods and
slide the unit in position.
' REVERSE glglr PrN PLATE FRoNT prN
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