AMF 1970-1971 Series XX User manual

Parts and Service Manual
1970- 1971 Series XX
Part No. 1002473
AMF WESTERN TOOL DIVISION
Parts and Service Department
Whiteford Road, York, Pennsylvania,
17402.717/848 -1177
"AMF INCORPORAT ED

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CONTENTS
TABLE Of CONTENTS
Page
INTRODUCTION ...................................................................... .. ............................................................................
PREDELIVERY INSTRUCTION S .......................................................................................................................... 1
Install Ski Assembly ............................................................................................................................................ 1
Ski Damper Adju st ment ....................................................................................................................................... 2
Install Windshield Assembly .................................................................................................................................. 2
Fuel Mixture Instructions ..................................................................................................................................... 2
Lubrication .......................................................................................................................................................... 3
SER VICE AND REPAIR .......................................................................................................................................... 3
Hood Removal an d Installation ............................................................................................................................ 3
Hood Assembly Repair ......................................................................................................................................... 3
Repl ace Lamp Assembl ies .................................................................................................................................... 4
Steering and Ski Assembly Alignment ................................................................................................................. 4
Steering Damper Adjus tm en t ............................................................................................................................... 4
To Remove Drive Chain ....................................................................................................................................... 4
Drive Ch a in Adjustment .......................................................................................................................................
To Remove Varia bl e-Speed Drive Belt .................................................................................................................
Variable -S peed Drive Belt Adjustment .................................................................................................................
To Remove Drive Clutch .....................................................................................................................................
5
5
6
6
Drive Clutch Alignment ....................................................................................................................................... 6
To Remove Driven Clutch .................................................................................................................................... 7
To Remove Brake Assembly ................................................................................................................................. 7
Brake Adjustment ................................................................................................................................................. 7
To Remove Carburetor .................... .. ..........................................................................._............................. .. ......... 7
Carburetor Adjustments .............................................................................................._........................................ 7
To Remove Fu el Pump ................................................................................................ _... ..................................... 8
To Remove Engine ....... ...... ... .... . ... ......... ....... ................... .. .............................. .... ... ..... _....... .. .............................. 9
To Remove Engine ... ............... .. .... ..... .... ...................... ... ........................................................... .. ... ............. .... .... 9
To Remove Gas Tank .......................................................................................................................................... 10
To Remove Muffler.............................................................................................................................................. 11
To Remove Muffler.............................................................................................................................................. 11
To Remove Exhaust Megaphon es ........................................................................................................................ 11
To Remove Sprocket Seals and Bearings .............................................................................................................. 11
To Remove Drive Sprocket Assembly ................................................................................................................. 11
To Remove Suspension As se mbly ................................................................................. _. ..................................... 12
To Remove Traction Belt .................................................................................................................................... 12
Traction Belt Adjustment .................................................................................................................................... 12
Traction Belt Alignment ...................................................................................................................................... 12
Traction Belt Tension Adjustment .......................................................................................................................
13
Suspension System Adjustment .......................................................................................................................... 13
Spark Plug Replacement ...................................................................................................................................... 13
Wiring Diagrams ................................................................................................................................................... 14
Troubleshooting. ........ ... ... .. .................................................... ... ........................................................................... 14
ILLUSTRATED PARTS LIST .........................................................................................._..................................... 19
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INTRODUCTION
This manual has been pr epared to provide all
authorized AMF Ski-Daddler Dealers, Distribu tor s
and
technicians with the instructions necessary to
service and maintain the 1970/1971 AMF High-
Perf ormance Series XX Ski-Daddler snowmobiles .
IMPORTANT:
The High-Performance Series XX
Ski
-Daddle r snowmobile is not covered by any AMF
warranty either expressed, implied or statutory.
The series classification for each snowmobile is
clearly shown on the left-hand side of the console
contro l panel. The Model Number and Serial Number
are permanently stamped on the nameplate attached
to the rear right-hand side of the main frame as-
sembly. When ordering accessories or replacemen t
parts, always indicate the correct Model Number
and Serial Number as shown on the ' nameplate.
The following list identifies the Ski-Daddler series
classification, corresponding model numbers and
e ngine designation covered in this manual.
SERIES
CLASSI
FICATION
MODEL NUMBER ENGINE
XX-1300 SD15M28A 292
XX-1340 SD15M26A 340
XX-1400 SD15M22B 399
XX-1440 SD15M23B 439
XX-1650 SD18M29A 650
XX -1800 SD18M30B 793
SD15M28A
111 [Manufacturer's engine code number
M =Manual start
Traction belt width in inches
Ski-Daddler
This manual is presented in two sections. The first
secti on, Maintenanc e, provides the instructions
necessary for maintenance and service while the
sec ond section, the Illustrated Parts List is pro-
vided to facilitate the ordering of spare and replace-
ment parts.
The Parts List section also contains a numerical
listing of all items shown in the Illustrated Par ts
List. Thus, if the part number is known but not its
applica tio n, refer to the numerical list. If the part
100 2 -1 73
INTRODUCTION
taSld
number is not known, locate the item on the illus-
tration to obtain the index number keyed to the
applicab le parts list.
If the information in this manual is not applicable to
all models, the exceptions will be noted and the cor-
rec t infor mat ion for the particular model will be
given.
PREDELIVERY IN STRUCTIONS
The 1970/1971 Ski-Daddlers are shipped completely
assembled except for th e windshield assembly and
the ski assembly.
The windshield and ski assemblie s will be found in
the shipping container. Carefully open the container
and immediately inspect the eqUipment for any
damage or missing items. The spindle pads and
locknuts will be found in the plastic bag. The
bushings and screws are installed on the spring
mounting bracket to retain the ski-dam per during
shippi ng.
IMPORTANT:
The owner must retain the Ski-
Daddler Inspection Record, Form No. 4477QA. This
form must be shown to the dealer should any claim
arise for missing or damaged parts.
Install Ski Assembly
• Remove the screw (3, figure 1) and bushing se -
curing the ski-damper to the spring mounting
bracket.
Figure 1

PREDEL I VERY INSTRUCTIONS
• Place the spindle pad (1) in the s pring mounting
bracket with the thicker section and the directional
arrow on the pad pointing forward .
• Secure the ski assembly to the lower end of the
spindle tube assembly by insert i ng the s crew (3) and
bushing through the s ki damper, spring mo untin g
bracket and spindle tube as ill u strated. Apply 30
foot-pounds torque to the locknut (2). Do not o ver-
tighten locknut as ski assembly should flo at fr eely
on the spindle.
NOTE: Be certain to install sk ii s with p iv ot of ski
damper forward and adju s ting n ut to out s id e ofSki-
Daddler as illustrated.
• Repeat procedure for oppos ite s ki .
NOTE:
Properly installed skii s should to e out 0- to
1/ 2- inch at the front end and s hould be symme t ric al
a bout the centerline of the sled. If ne c ess a ry, re f er
to paragraph Steering and Ski As s em bl y Al ign m ent
procedures.
Ski Damper Adjustment
To adjust the sk i damper ass em blies, rem ove the
cotter pin (figure 1) and tig ht en or loo se n th e ad-
ju s ting nut as required to ach iev e t he de sire d
tension. Replace cotter pin and repeat p roc e du re
on oppos ite ski a ss embly.
Install Windshield As sembly
• Disco n nect hood ha rness at the quick d is -
connect.
• Remove hood assembly. Re fer to Hood R em o val
and· Installation procedure.
• Back off the locknut (figu re 2) and r em o ve the
7/8 - inch length screw us ed to se c ur e th e hood
harnes s clip and the end of th e ri ght-h an d moun t ing
st rip to the hood. NO TE: The hood h arness clip,
locknut and 7/8 - inch le ngth sc re w (figu re 2) are
us ed on the 15- inch trac k sleds only.
• Remove the remaining s crews secu ri ng th e
right- and left-hand mounting s tr i ps to th e hood.
Remove the mounting strips.
• Remove the protective pla s tic cover fr om the
windshield. Place the windshield in po s ition on th e
hood
assembly. Replace the mo unting st r ips as
shown in figure 2.
2
MOUN TING
ST RIP.
RH
7/8 -I NCH LONG
ONLY)
WIN DSH IELD TR IM
M OUNTING
STRIP . LH
•
TOE OUT 0- TO 1 /Z - IN CH MAX I MUM
15 -I NCH TRACK SLED SH O WN
Figure 2
• Usin g th e original screws, loosely secure the
mo unting strips and windshield to the hood as s embly
st arting at the center and working to the sides . Be
certain to position the 7/8 - inch l ength screw in the
end position shown in figure 2.
• Engage the en ds of the mounting strips over the
t rim st rip on t he winds h ield and then tighten the
screws , startin g at the sides and working to the
center. Rem o ve the protective _ ~overing from the
mountin g strips. NOTE: Check mounting s tr ips
for
sharp edges or corners . Use a fine - tooth file
to sm ooth any sh arp edges and corners.
• Attach the hood harness clip to the 7/8 - inch
length screw and secure wi th locknut.
• Repla ce the hood assembly.
Fuel Mixture In structions
r- , -W- A- R-N- IN -G-"I
Never fill the gaSOline tank while the
engine is hot. Wipe off any spilled
gasoline b ef o re attempting to start
engine.
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The correct oil-to-ga soline ra ti o is 20: 1 (20 parts
re gular gasoline to 1 p art oil). Too much oil will
ca us e carbon deposits. Too lit tle oil or a poor mix
will cause insufficient l ubri ca tion an d possible
engi ne damage.
IM PO RT ANT: Gasolin e and o il should be mixed at
temp er ature s above ze ro. At temperatures below
ze ro gas and oil mix with di ffi cult y.
Fuels containing additiv es are not rec ommended for
use in Ski-Daddler engines. For mixi ng wit h gaso-
lin e, use Citgo, Rislon e or Kendall o il prepa r ed
excl u sively for use in a ir-cooled, 2-c y cle engines .
IMPORTANT: Some outboard motor o il s contain an
addit i ve that works we ll in outboa rd motors tha t
ope
rate at much lower temp e ratur es because they
ar e water cooled. However, th e addi ti ves may cause
spark plug fouling in the air-cool ed engi nes u sed on
Ski-
Daddler snowmobil e s.
U se a mixture of gasolin e and o il as shown in the
Fuel Mixture Chart. Neve r u se g asoline left over
fr om the summer or previous win ter.
FUEL MIXTURE CHA RT
OIL (Ounces )
o 4 8 12 16 20 24 28 32 36 40
5
4
3
2
/
o
GA S OLINE
(Gallons)
v
/"
/
./
-"
/ V
./
/"
V
./
/ V
./
~
"
./
/
.,
~
u. s. Ga ll on,
I m pe ,;~ 1 Ga l ion, T-
GASOLINE/OIL RATlO- 20 to 1
Mix the gasoline and oil thoroughly in a clean con-
tain er kept for this purpos e only. The best way to
ens ure a good mix is to pou r th e oil into a container
with about one gallon of ga s oline and mix thoroughly.
Then add additional amounts of ga s olin e as shown on
the Fuel Mixture Chart. Fill Ski-D addl er gas t ank
from this separate container of mix ed fue l. Use a
funnel with a
fine-screen s train er when filling th e
tank.
1002473
3
PREDELIVERY INSTRUCTIONS USia
Lubrication
A low-temperature grease must be applied to the
zerk fittings located on the steering spindle tube s;
after apprOximately each 20 hours of use. The chain
case housing must be checked after each 10 hours of
use and No. 2 lithium bearing grease added as
required.
The bearing cup retainers that hold the drive and
idler sprocket seal bearings should be repacked with
No. 2 lithium bearing grease whenever the bearings
are removed during normal maintenance. No.2
li thium b ea ri ng gr ease ma y als o be applie d to the
i nside of the d rive and idler sprocket bearing re-
ta in ers du ring nor mal main ten ance .
Grease may also be applied as required to the wear-
plates and U-strap securing the steering column to
the roll bar.
SERVICE AND REPAIR
Hood Removal and Installation
• To remove the hood and headlight assembly,
disconnect the hood and the sled wiring harness at
the quick-disconnect below the console on the right -
hand
side of the sled. Release the hood latch
assemblies and then remove the hood and headlight
assembly by lifting back section first.
• To install the hood and headlight assembly,
place the hood in position on the sled so that the
forward hood clip and the bottom edge of the hood
engages the clips along the inside edge of the
bumper.
• Engage the left- and right-hand latch assem -
blies and insert safety pins to secure the hood· to
the main frame .
• Connect the wiring harness using the connector
plug located below the console on the right-hand side
of the sled.
Hood Assembly Repair
AMF Fiberglass Repair Kits are available through
your authorized AMF Distributor. For large
re p airs, order AMF Fiberglass Repair Kit No.
1510693.
Smaller repairs can be made with Repair
Kit No. 1510765. Paint all repaired areas on the
hood using AMF -Orange color paint available in
easy-to-use spray container, AMF Part No.
1510828.
Follow the instructions in the kit when
m
aki ng repa i rs.

SERVICE AND REPAIR
Replace Lamp Assemblies (15 -Inch Sleds Only)
Headlight. Tb replace the headlight bulb, raise the
headlight assembly; remove the screws securing the
cover assembly and remove the cover assembly.
Remove the defecti ve bulb and replace with newbulb.
See illustrated parts list for correct replacement
part numbers.
Taillight. Remove taillight l ens to expose the tail-
light bulb. Remove the defective bulb and replace
with a new bulb. See illustrated parts list for cor-
rect replacement part numbers.
Steering and Ski Assembly Alignment
Good steering ability requires that the skis be
properly set and aligned with the sled body when
th e steering handle is placed in the straight-ahead
position. Remove any play in the skis by pulling
the skis toward the center of sled before taking
measurements. To determine that the skis are
properly aligned, measure the distance between the
inside edges of the skis at the front end and at the
rear. Properly aligned skis should toe out 0- to
1/2-inch maximum at the front. Therefore, the
overall measurement at the front end of the skis
should be no more than 1/2-inch greater than at the
rear. If the skis or steering mechanism are not
properly set, adjust as follows:
• Place steering handle in a straight-ahead
position.
• Remove the hood assembly. Refer to Hood
Removal and Installation.
• Remove the bolt (1, figure 3), two spacers (2),
bottom spacer and locknut securing the rod end
bearing (3) to the spindle arm (6).
• Loosen the jam nuts (4) securing both rod end
bearings (3) to the tie rod (5).
NOTE: If both skis need adjustment, repeat pro-
cedure for the opposite ski.
• Move the affected ski into proper alignment and
recheck measuring points to insure that the skis toe
out 0- to 1/2 -inch maximum at the front end and are
in the same orientation with the sled body as shown
in figure 2.
• With skis properly set and steering handle in the
straight-ahead position, rotate tie rod (5, figure 3)
as required to bring rod end bearing (3) in line with
the spindle arm (6).
4
Figure 3
• Secure rod end bearing (3) to spindle arm (6) as
illustrated. Check for proper alignment and then
tighten jam nuts (4) to secure both rod end bearings.
NOTE: If a greater adjustment is required than that
permitted by the steering linkage assembly, it will
be necessary to align the ski by making the adjust-
ment at the spindle tube assembly as follows:
• Remove screw (5, figure 4) and locknut (6) se-
curing spindle tube assembly (7) to spindle arm (8).
• Remove spindle arm (8) and rotate ski and
spindle tube one notch in the required direction;
replace and secure spindle arm to the spindle tube.
Apply 20 foot-pounds torque to the locknut (6).
• Recheck the skis for proper toe out and align-
ment as previously described.
NOTE: Ski-damper adjustment is not normally re-
quired during Ski-alignment procedures. However,
if adjustment is desired, tighten or loosen th e ad-
justing nut shown in figure 1 as required to obtain
the desired tension.
Steering Damper Adjustment
The steering damper assembly (figure 3) is set at
the factory and should require no further adjust-
ments.
To Remove Drive Chain
• Remove the hood assembly. Refer to Hood
Removal and Installation.
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! CAUTION l
Always disconnect spark plug wires
before working on the engine or drive
elements.
• Remove the locknut securing the chain cover top
and remove chain cover top and spacer sleeve.
• Loosen the bolts (1, figure 4) on both cam up-
rights (2) and rotate the cam and shaft (3) as re-
quired to loosen the chain tension. During reassem-
bly, apply 30 foot-pounds torque to the bolt (1).
• Remove the cotter pin, slotted nut and washer
securing the top sprocket to the driven clutch shaft.
Remove the top sprocket and chain together.
• Reassembly is th e reverse of removal. Per -
form drive chain adjustment procedures and add
No. 2 lithium bearing grease as required to the
chain case.
Drive Chain Adjustment
A properly adjusted drive chain (figure 4) should
have a 1/8 - to 1/4-inch slack. Check and adjust
chain as follows:
• Remove the locknut securing the chain cover
top and remove chain cover top and spacer sleeve.
• Rotate the upper sprocket to tension one side of
the chain and then check the opposite side for proper
slack. If adjustment is required, loosen the bolts
(1) securing the cam uprights (2) on each side.
During reassembly, apply 30 foot - pounds torque to
the bolts (1).
• Rotate the cam (3) counterclockwise to tighten
or until the chain is properly tensioned. Hold the
cam in this position while tight ening the cam upright
bolts (1) on each si de. Be certain the lateral align -
ment between the drive clutch and the driven clutch
(4) is maintained while the cam upright bolts are
tightened.
• Recheck chain tension before replacing the
chain cover, top and spacer sleeve.
To Remove Variable -Speed_ Drive Belt
• Remove the drive chain. Refer to paragraph
To Remove Drive Chain.
• Remove the clutch guard assembly.
I002·17l
5
~I SERVICE AND REPAIR leSla~
• Loose n the locknut (8, figure 3) and serrated
washer (7). During reassembly, apply 10 foot-
pounds torque to the locknut (8).
• Push the driven clutch toward the drive clutch
to permit removal of the variable-speed drive belt
from the drive clutch. If necessary the drive belt
can be removed from the drive clutch after the
driven clutch is removed from the bearing clamps .
• Remove the locknuts (7, figure 6) securing the
bearing clamps (8) and remove the bearing clamps.
During reassembly, apply 5 foot-pounds torque to
the locknuts (7).
• Lift the driven clutch and drive belt clear of
the brake assembly and remove the variable-speed
drive belt.
• Install replacement drive belt. Use AMF Part
No. 37880 on Models SD15M26A and SD15M28A-
AMF Part No. 37492 on Models SD15M22B and
SDI5M23B; AMF Part No. 34635 on Models SDI8M-
29A and SD18M30B.
NOTE:
Variable-speed drive belt installation pro-
cedures are the reverse of removal except that the
belt must first be placed around the driven clutch
and then around the drive clutch. Afterin s tallation,
perform the drive chain adjustment, variable-speed
belt adjustment and the drive clutch alignment
procedures.
Figure 4

SERVICE AND REPAIR
Variable-Speed Drive Belt Adiustm~nt
Proper tension for a new drive belt should be ob-
tained when the clutch centers are set to the B
dimension shown in figure 5 for the applicable model
snowmobile.
IMPORTANT: Do not use antislip belt dressing.
Belt slippage is a safety feature which prevents
overstressing drive-system components .
• To adjust drive belt tension, loosen the locknut
(8, figure 3) securing the clutch rod tensioner to
the main frame assembly.
NOTE: If the drive belt is wearing unevenly, check
alignment as described in Drive Clutch Alignment
procedures.
• Move the driven clutch (9) in the direction re-
quired to obtain proper belt tension. Hold this posi-
tion while tightening the locknut to secure the clutch
rod tensioner. Be certain the washer (7) and bar
serrations are properly engaged. Apply 10 foot-
pounds torque to the locknut (8).
To Remove Drive Clutch
• Remove the hood assembly. Refer to Hood
Removal and Installation.
! CAUTION !
Always disconnect spark plug wires
before working on the engine or drive
elements.
• Remove the clutch guard assembly.
• Loosen the locknut (8, figure 3) and serrated
washer (7) securing the clutch rod tensioner to the
main frame. During reassembly, apply 10 foot-
pounds torque to the locknut (8).
• Push the driven clutch toward the drive clutch
to permit removal of the variable-speed drive belt
from the drive clutch. If necessary remove belt
after drive clutch is removed from engine.
• To remove the drive clutch, remove the clutch
adapter bolt and washer. If necessary, use a clutch
puller and remove the drive clutch. NOTE: During
reassembly on Models SD15M28A and SD15M26A
only,
apply 50 to 60 foot-pounds torque to the clutch
bolt. All other models require 70 ± 5 foot-pound s
torque.
6
• Reassembly is the reverse of removal. Per-
form variable-speed dri ve belt adjustment and drive
clutch alignment procedure s.
Drive Clutch Alignment
• Remove the hood assembly. Refer to Hood
RemOVal and Installation.
Always disconnect spark plug wir es
before working on the engine or driv e
elements.
• Remove the clutch guard.
• Loosen the engine holddown nuts (figur e 5) se-
curing the engine supports to engine mount straps .
• Place a straightedge on the fixed face of th e
drive clutch and move th e engine until th e offset
between the straightedge and the front and rear
edges of the driven clutch is set to the A dimension
as shown in figure 5. Rotate driv en clutch 90-
degrees and repeat proc e dure.
• Tighten engine holddown nuts and recheck
alignment. Apply 25 foot-pounds torque when
tightening the engine holddown nuts.
A
0. 24
0.24
0.26
0.26
0.26
0.26
B
12·1/2
12-1/2
12·1/2
12·1/2
12·1/2
12·1/2
c
(TORQUE)
FT - LB MODEL NO.
55 ±.5 S D15M28A
55.± 5 S D15M26A
70 .± 5 SD15M22B
70 .± 5 SD15M23B
70 .± 5 SD18M29A
70 .± 5 SD18M30B
Figure 5
ENGINE CLUTCH
292 780M
340 780M
399 9·R
439 9·R
650 11·R
793 11·R
HOLDDOWN
NUTS
VIEW 0
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To Remove Driven Clutch
NOTE: The procedures required to remove the
driven clutch are the same as those desc ri bed in
paragraph To Remove Variable -S peed Drive Belt.
To Remove Brake Assembly
• Remove hood assembly . Refer to Hood Removal
and Installation.
! CAUTION l
Always disconnect the sparkplugwires
before working on the engine or drive
elements.
• Disconnect brake cable and housing (3, figure 6)
at brake mounting bracket and at brake actuating
lever.
• Remove the bolts and lockwashers securing the
mounting bracket to the driven clutch mo untin g.
• Remove the brake assembly.
• Installation procedures are the reverse of re-
moval. Refer to Brake Adjustm ent proc edures.
Brake Adjustment
• To adjust the brake pad s (5, figure 6) to the disk
(1), remove the cotter pin (2) and tighten or lo o sen
Figure 6
I 'If).! 17 i 7
~I SERVICE AND REPAIR If4
Si
aij
the castle nut (4) as required to permit the brake
pads (5) to just clear the brake disk. Reinstall the
cotter pin. To adjust for excessive play in brake
cable or lever position, loosen jam nuts (6) and
move brake housing (3) as required. Tighten jam
nuts.
To Remove Carburetor
• Remove the locknut securing the throttle rod
screw to the carburetor linkage. Remove th e throttle
rod screw and jam nuts.
• Remove the screws securing the ram tube to the
carburetor and remove the ram tube.
• Disconnect the fuel lines at the carburetor.
Wipe up any spilled gasoline immediately. Be cer -
tain to note the position of the gas line and impulse
lines to insure proper reassembly.
• Remove the jam nuts and lockwashers securing
the carburetor to the intake manifold and remove the
carburetor.
• Remove the gasket. Do not damage the gasket
if required for reassembly. NOTE: Replacement
carburetors are supplied with a new gasket.
• Installation is the reverse of removal. Adjust
the carburetor as described in the Carburetor
Adjustment procedures.
Carburetor Adjustments
The carburetors used on Models SD15M22B and
SD15M23B are float type carburetors that utilize
external pumps. The high- and low - speed adjust-
ment screws for these carburetors are located on
top of the carburetor and are easily identified by
the letters HI and LO. The adjustment screws for
all other type carburetors are located on the sides
as shown in figure 7.
When
adjusting the carburetor, best results will be
obtained if the adjustments are made on a warm
engine. During carburetor adjustments, DO NOT
FORCE ADJUSTMENT SCREWS INTO SEATS.
• TO ADJUST CARBURETOR - Close the high-
speed jet (DO NOT FORCE). Then open the high-
speed jet (figure 7) to the settings shown on the
carburetor settings chart for the particular engine
(see figure 8).

~t&:4Mlal SERVICE AND REPAIR I~
!~~CAUTION
The engine can be seriously damaged if
operated with a lean gas mixture (high-
speed jet turned in too far) .
• Turn the low speed jet (idle-mixture screw)
shown in figure 7 all the way in (DO NOT FORCE),
then open as shown in figure 8 for the particular
engine. This adjustment controls the mixture at
idling speeds. A lean idle mixture will result in
poor acceleration.
Figure 7
Keep the idle speed slower than the clutch engaging
speed by adjusting the idle-speed screw. NOTE: Do
not use the low-speed jet to adjust for idle speed.
To Remove Fuel Pump-
NOTE: Figure 7 shows a throttle-wire. If the
throttle plate fails to open completely when the
throttle control lever is depressed, loosen th e
throttle-wire adjustment screw and readjust the
wire as required to open the throttle.
Models SD1SM22a and SD1SM23B only
!~ ~~~TION !
Always disconnect the sparkplugwires
before working on the engine or drive
elements.
CARBURETOR SETTINGS CHART
SERIES
MODEL NO. CLASSIFICATION ENGINE HIGH-
SPEED JET LOW-SPEED JET
+ 1/8 0 +
1/8
SD15M28A XX-1300 292 1 _ 0
pen
1- 1/8 _ 0 Open
SD15M26A XX -1340 340 1 +
1/8
_ 0 Open +
1/8
1-1/8 _ 0 Open
SD15M22B XX-1400 399 1 + 1/8 0
_ 0 pen
1-1/2 + 1/8 Open
- 0
SD15M23B +
1/8 0 +
1/8
XX -1440 439 1 _ 0
pen
1-1/2 _ 0 Open
SD18M29A XX-1650 650 +
1/8
7/8 _ 0 Open +
1/8
1-1/8 _ 0 Open
SD18M30B XX-1800 793 7
/8 ~ ~/8 Open +
1/8
1-1/8 _ 0 Open
-
The above carburetor settings are for factory stock engines. Modified engines, exhaust systems,
carburetion and various altitudes may require different settings for satisfactory operation.
Figure 8
8 1002473
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• Disconnect the gasoline lines at the fuel pump.
Note
the pOSition of the lines to insure proper re-
assembly. Disconnect the impulse line. Wipe up any
spilled gasoline immediately.
• Remove the locknut and washer securing the
fuel pump to the mainframe. Remove the fuel pump
and mounting bracket as a unit.
• Reassembly is the reverse of removal.
To Remove Engine -Models SD15M28A,
SD15M26A, SD15M22B and SD15M23B only
• Remove the hood assembly. Refer to Rood
Removal and Installation.
!~~CAUTIO~
Always disconnect the sparkplugwires
before working on the engine or drive
elements.
• Remove the drive clutch. Refer to paragraph
To Remove Drive Clutch.
NOTE: The Illustrated Parts List section of this
manual contains detailed exploded views of the
engine and support assemblies whichwill be helpful
if referred to during engine removal procedures.
For engine maintenance instruction, refer to the
engine manual supplied with each sled.
• Remove the caps crews and washers securing
the carburetor heat shield to the intake manifold
and remove the heat shield.
• Disconnect the gas lines at the carburetors.
Disconnect impulse lines at the engine. Wipe up any
spilled gasoline immediately. Note the position of
all lines to insure proper reassembly.
• Remove the capscrews and spring lockwashers
securing the left- and right-hand intake manifold to
the engine. Remove the intake manifolds, carbure-
tors and ram tubes as a unit.
• Remove the engine-to-manifold gasket if re-
quired for reassembly. NOTE: New, replacement
engines are supplied with new engine-to-manifold
gaskets.
• Remove the exhaust system on Models SDI5M-
22B and SD15M23B only. Refer to paragraph To
Remove Muffler.
1 00 2473
9
ERVICE AND REPAIR
USia
• Remove the heat shield attach ed to the roll bar
and main frame between the engine and the muffler.
• Disconnect the engine wiring harne ss and
loosen or remove all wiring holddown clips. Dis-
connect the ground lead.
• Remove the locknuts, washers, rubber spacers
and bushings securing the engine and engine
mounting straps to the main fram e. NOTE: The
carriage bolts are held in position with Tinnerman
nuts and need not be removed. Do not remove the
shockmounts unless it is necessary to replace them.
During reassembly, tighten the locknuts sufficiently
to allow a 5 /16 -inch clearance between bottom of
the shock mount and top surface of the main frame.
IMPORTANT: Be certain all wiring and gasoline
lines are clear before attempting to remove the
engine.
• Lift the engine and engine mounting straps until
the straps are clear of the carriage bolts and re -
move
the engine and straps as a unit.
• Release the exhaust manifold at the engine on
Models SD15M28A and SD15M26A only.
Refer to
paragraph To Remove Muffler.
• Remove the bolt and washers securing the
engine to the engine mounting plate and remove the
engine. During reassembly, apply loc - tite to the
bolt threads and tighten bolts to 18 foot-pounds
torque.
• Installation is the reverse of removal.
To Remove Engine -
Models SD18M29A and SD18M30B only
• Remove the hood assembly. Refer to Hood
Removal and Installation.
I CA~TION
Always disconnect the sparkplugwires
before working on the engine or drive
elements.
• Remove the drive clutch. Refer to paragraph
To Remove Drive Clutch.
NOTE: The Illustrated Parts List section of this
manual contains detailed exploded views of the
engine and support assemblies which will be helpful
if referred to during engine removal procedures.

~t.!2131 SERVICE AND REPAIR I~
For engine maintenance instructions, refer to the
engine manual supplied with each sled.
• Disconnect the gas lines at the carburetors.
Disconnect impulse lines at the engine. Wipe up any
spilled gasoline immediately. Note the position of
all lines to insure proper reassembly.
• Disconnect the throttle cable at the carburetor
linkage and remove the metric nuts and lockwashers
securing the carburetors and carburetor linkage to
the engine. Remove the carburetors and linkage as
a unit. On Model SD18M29A, remove the carburetor,
linkage and intake manifold as a unit.
• Remove the carburetor heat shield.
• Remove the engine-to-manifold gasket if re-
quired for reassembly. NOTE: New, replacement
engines are supplied with new engine-to-manifold
gaskets for Model SD18M29A. On Model SD18M30A,
new gaskets are supplied with the carburetors only.
• Disconnect the engine wiring harness and
loosen or remove all wiring holddown clips. Dis-
connect the ground lead.
• Remove the clamps securing the exhaust mega-
phones to the megaphone support weldment. Release
the extension springs at the engine and remove the
megaphones. Note the position of the clamps to
insure proper reassembly.
• Remove the bolts and washers securing the
engine mounting straps to the main frame and shock
mounts. Remove the engine and mounting straps
clear of the sled. During reassembly, do not tighten
the engine mount bolts until after completing clutch
alignment. After clutch alignment, tighten engine
mount
bolts to 9 foot-pounds torque.
NOTE: If more clearance is desired, remove the
seat assembly. The locknuts and washers securing
the seat to the main frame are accessible through
the seat tote pouch.
• Remove the bolts and washers securing the
engine mount frame to the engine. Remove the
engine. During reassembly, apply loc-tite to the
bolt threads.
• Installation is the reverse of removal.
To Remove Gas Tank
• Remove the hood assembly. Refer to Hood
Removal and Installation.
10
1 CAUTION !
Always disconnect spark plug wir es
before working on the engine or drive
elements.
• Check gas cap and indicator assembly to be
certain tank is empty, or nearly empty.
• Remove the gas cap and indicator assembly (1,
figure 9).
• Remove the bolts (3) and washers securing the
gas spill chute (2) to the main frame and remove the
gas spill chute.
• Disconnect the tank - to-carbure tor gas lines (6)
at the gas tankoutletfitting (5). Wipe up any spilled
gasoline immediately.
• Remove the gas tank (4) by carefully sliding the
tank up and away from main frame. IMPORTANT:
Do
not damage the gas tank outlet (5) when removing
the tank.
Do
not attempt to make any repairs to
the gas tank , Use extreme care when
removing the gas tank. Do not remove
tank near flame or open fire.
• Gas tank installation procedures are the re-
verse of removal. NOTE: If the original tank is not
to be installed, it will be necessary to remove the
gas tank outlet (5) and the attached gas line filter;
also the pressure relief valve (8). These items are
to be i nstalled on the replacement tank.
Figure 9
1002473
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To Remove Muffler-
Models SD15M28A and SD15M26A only
• Remove the hood assembly . Refer to Hood
Removal and Installation.
Always disconnect the sparkplugwires
before working on the engine or drive
elements.
• Loosen the clamp securing the muffler to the
dual-exhaust manifold.
• Loosen the bolt and nut securing the muffler to
the mounting band assembly. Remove the muffler.
• Installation procedures are the reverse of
removal.
To Remove Muffl er-
Models SD15M22B and SD15M23B only
• Remove the hood assembly. Refer to Hood
Removal and Installation.
! CAUTI~~
Always disconnect the sparkplugwires
before working on the engine or drive
elements.
• Remove the screws, washers and locknuts se-
curing the muffler band asse-mblies to the muffler
bracket and to the heat shield.
• Remove the screws, washers and locknuts se-
curing the hea t shield to heat shield support attached
to the roll bar. Remove the heat shield.
• Remove the retaining rings securing the muf-
fler weldment to the exhaust manifolds.
• Remove the muffler weldments. Note the posi-
tion of both mufflers to insure proper reassembly.
• Remove the muffler band assembly from each
muffler.
• Installation procedures are the reverse of
removal.
1002473
11
SERVICE AND REPAIR
To Remove Exhaust Megaphones -
Models SD18M29A
and SD18M30B only
NOTE: Model SD18M30B has a three megaphone
system whereas Model SD18M29A utilizes a two
megaphone system.
• Remove th e hood assembly. Refer to Hood
Removal and Installation.
I ~~UTIO~:]
Always disconnect th e sparkplugwires
before working on the engine or drive
elements.
• Remove the clamps securing the megaphones to
the megaphone support weldment. Note the position
of each clamp to insure proper reassembly.
• Release the extension springs securing the
megaphones to the engine exhaust manifold and re-
move the megaphones.
• Installation procedures are the reverse of
removal.
To Remove Sprocket Seals and Bearings
• Sprocket seals andb earings are located on each
end of the drive sprocket assembly drive shaft. To
replace the seals or bearings it will be necessary
to remove the drive sprocket assembly as described
in the follOwing paragraph.
To Remove Drive Sprocket Assembly
• Remove the hood assembly and set the machine
on its right-hand side.
f C~UTION
Always disconnect spark plug wires
before working on the engine or drive
elements.
• Remove the suspension assembly. Refer to
paragraph To Remove Suspension Assembly.
• Remove the lower sprocket from the drive
sprocket shaft and remove the sprocket and chain
as described in paragraph To Remove Drive Chain.

SERVICE AND REPAIR
• Using a screw driver, carefully pry the oil
seals (figur e 10) away from the bearings at each
end of the drive shaft.
• Remove the carriage bolts and nuts securing
the bearing retainers to each side of the main frame.
Remove the retainers. During reassembly apply No.
2
lithium bearing grease to the bearing retainers.
• Move the drive shaft and sprocket assembly
toward the chain side until the opposite end of the
shaft clears the other side. Remove the drive
sprocket assembly. NOTE: With the removal ofthe
drive sprocket assembly, the traction belt will also
be free for removal.
• To replace the sprockets, remove the ball
bearing, oil seal, collar and idler wheel. Remove
the screws and nuts securing the support plate and
sprocket to the drive shaft and sprocket plate
assembly. Remove the sprocket.
• Reassembly is the reverse of removal . During
reassembly follow instructions outlined in the para-
graphs Traction Belt Tension Adjustment, Traction
Belt Alignment and Drive Chain Adjustment.
Figure 10
To Remove Suspension Assembly
• Remove the hood assembly and set the machine
on its right-hand side.
\: CAUTION
Always disconnect spark plug wires
before working on the engine or drive
elements.
12
• Remove the screws (figure 11) andlockwashers
securing the back end of the suspension assembly to
main frame.
• Pivot the suspension assembly and traction belt
about the front axle to approximately 90 degrees.
• Remove screws and lockwashers securing the
suspension assembly to the front end of the main
frame and remove the suspension assembly.
• Installation is the revese of removal. During
reassembly, follow the instructions outlined in
paragraphs Traction Belt Tension Adjustment,
Traction Belt Alignment and Suspension System
Adjustment.
To Remove Traction Belt
To remove or replace the traction belt itis neces-
sary to first remove the suspension assembly and
then the drive sprocket assembly. Refer to the
applicable paragraphs for removal procedures.
IMPORTANT: When installing the traction belt,
follow the instructions outlined in paragraphs trac-
tion Belt Tension Adjustment, Traction Belt Align-
ment and also recheck Suspension System Adjust -
ment.
Traction Belt Adjus tment
IMPORTANT: The traction belt must be checked
regularly for proper alignment and tension. When
necessary to adjust the belt, first perform the trac-
tion belt alignment and then complete the traction
tension adjustment.
Traction Belt Alignment
• Set the snowmobile on a level surface and
raise the back end.
• Stand to the rear of sled and visually check the
space between the slide rail and the edges of the
track. NOTE: On a properly aligned track this
space shoul d be the same. Start the engine and
again visually check to be certain the track remains
centered while the track is running.
• If the track is not centered, stop the engine and
on
that side where the edge of the track is closest to
the slide rail, rotate the adjusting screw (figure 11)
until
track is centered. Pull the track for a few
revolutions and then start the engine and recheck
alignment. Stop the engine and lock the adjustment
screw in this pOSition.
1002473
•

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lOCKNUT~
• After track alignment is complete, check track
tension as described in the following paragraph.
Traction Belt Tension Adjustment
• Set the snowmobile on a clean, flat surface and
raise the back end of the sled.
• Check traction belt tension by firmly pulling
the track downward at the center of the track. A
properly tensioned track should have a 1- to 2-
inch clearance between the Hi-Fax runner and the
track cleats at the appro~mate bottom center of the
track. NOTE: Do not attempt this with the engine
running. Traction belt cleats are sharp and must be
handled carefully.
• If adjustment is necessary, loosen the locknuts
(figure 11) on each side of the sled and rotate the
adjusting screws as required to obtain proper track
tension. IMPORTANT: Adjust both screws equally
so as not to disturb the track alignment. Retighten
the locknuts on both sides of the snowmobile.
! CAUTION !
Never run the engine inside a building
without first opening all doors and win-
dows to insure proper ventilation.
• Raise the back end of the snowmobile until the
track clears the ground. Start the engine and allow
I 002-17J
ERVICE AND REPAIR
PROPER TENSION
1- TO 2-INCH PUll
ADJUS T IN G SCREW
Figure 11
13
the track to rotate several turns. Then, stop th e
engine and repeat the track tension adju s tment pro -
cedure to ensure that proper tension is mai n ta i ned .
Suspension System Adjustment
The suspension system may be adjusted for a s oft or
firm ride, or for varying snow conditions. If a
. firmer ride is desired, adju st the locknut s (figure
11) to tighten the eyebolts located on each side of the
track. Loosen the eyebolts if a softer ride is de -
Sired. Adjust front or rear sets of eyebolt s equally.
Spark Plug Replacement
To maintain top engine performance the condition
of the spark plugs should be checked periodically
and the gap reset to 0.020- inch us ing feeler gauge.
During reassembly apply 18 to 20 foot pounds
torque.
Spark plug condi tion may be determined by the colo r.
A carbonized plug is black; a burnt plug is pale gray,
whereas a normal functioning spark plug is brown.
When replacing spark plugs, use AMF - approved
spark plugs to insure proper spark plug he at ranges
for a particular engine. NOTE: The Spark Plug
Chart is provided to identify spark plug s for light
or severe service.

~t ... 5iiMI31 SERVICE AND REPAIR I~
SPARK PLUG CHART
MODEL NUMBER ENGINE
SD15M28A (XX-1300) 292
SD15M26A (XX-1340) 340
SD15M22B (XX-1400) 399
SD15M23B (XX-1440) 439
SD18M29A (XX-1650) 650
SD18M30B (XX-1800) 793
*Optional
Wiring Diagrams
Electrical wiring diagrams shown on the following
pages are provided for the trained technicians using
this manual. Each diagram is identified with the
model number of the snowmobile to which it applies.
Troubleshooting
ENGINE HARD TO START. Fuel line blocked or
leaking; ruptured fuel-pump diaphram; water in
fuel, flooded or loose impulse line; ignition or
switch wiring loose or grounded; spark plug(s)
fouled or faulty; contact breaker points pitted or
burned; quick-kill switch in off pOSition.
ENGINE STOPS. Fuel tank empty; fuel flow ob-
structed; ignition system faulty. Spark plug(s)
fouled or dirty. Engine too hot and pistons seizing;
carburetor setting too lean or incorrect grade of oil
being used, impulse line loose.
ENGINE OPERATES IRREGULARLY. Sparkplug(s)
loose, fouled or faulty; ignition switch wiring
shortSd.; carburetor out of adjustment or dirty.
Engine holddown bolts loose; ignition timing off.
ENGINE WORKING
FOUR-STROKE. Choke shut;
carburetor settings incorrect; dirt preventing car-
buretor inlet needles from seating properly.
ENGINE LOSES POWER. Poor compression due to
loose head and crankcase bolts. Faulty ignition;
timing; piston rings sticking due to the use of im-
proper oil. Carbon deposits in cylinder.
14
LIGHT SERVICE SEVERE SERVICE
38058 (N60
or *41XL)
38068 (N57 or 41XL)
38058 (N60 or *41XL)
38068 (N57 or 41XL)
38068 (N57 or 41XL) 38068 (N57
or 41XL)
38068 (N57 or 41XL) 38068 (N57 or 41XL)
1002607 (K7 or SN82F) 1003068 (K57R)
1002996 (L81 or S40F6) 1003069 (L54R)
ENGINE BACKFIRES THROUGH CARBURETORS.
Carburetor fuel-supply channel clogged. Carbu-
retor set too lean.
ENGINE BACKFIRES THROUGH EXHAUST. In-
correct or faulty spark plug(s); faulty ignition coil
or condenser; loose ignition wiring.
ENGINE OVERHEATS. Insufficient or incorrect
grade oil in fuel mixture; carburetor or fuel line
partly clogged; carburetor setting too lean; ignition
timing too slow.
BRAKES. Excessive play in handbrake due to loose
brake cable or worn pads.
TRACTION BELT. Poor traction; check traction
belt for alignment and tension; worn sprockets.
CLUTCH. Automatic clutch fails to engage at
proper RPM's (see figure 12). Check variable-
speed drive belt for proper tension and alignment.
CLUTCH ENGAGEMENT SPEEDS
CLASS ENGINE ENGINE
RPM
XX-1300 292 4300 ±.300
XX-1340 340 4300
±300
XX-1400 399 4400 ± 300
XX-1440 439 4400 ± 300
XX -1650 650 4300
±300
XX-1800 793 4300 ± 300
Figure 12
1002473
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EXCESSIVE FUEL CONSUMPTION. Carburetor
fuel line or gas tank leaking; choke closed; incor-
rect carburetor setting.
SKI ASSEMBLY. Poor steering ability due to loose
skis; worn wear rod. Poor riding characteristics
due to loose or defective ski-dampers.
I
I
L
WHITE
BLACK
WHITE -RED
RED
SERVICE AND REPAIR
STEERING. Poor steering a bility caused by im-
properly adjusted skis; steering linkage loose or out
of
adjustment. U -bracket bolts on roll bar too tight
or too loose. Spring, U- bracket loose.
THROTTLE CONTROL. Excessive play in throttle
control lever caused by loose throttle control cable.
MODEL SD18M29A
ENGINE
HIRTH 650
TACHOMETER
GRE~;o
CBLACK
BLACK
GROUND AT ENGINE
= STARTER BOLT
IGNITION SWITCH
OFF RUN
\ \ I /
QUICK KILL
SWITCH WHITE WHITE
-RED
~- ~--+ ______ ~ __________ ~ ______ ~G~R=E=E~ N ____ ~3~ lb~~ ~~ ~
RED 31
10024 73 15

....
0'1
MODEL SD18M30B
IGNITION SW I TC H
OFF
,
Q UI CK KILL
S WI TCH
t:l ~
~ a:
] ~~ J
WHITE
' a_ -I-- 77' ( '--7,)') ;J»" • I ~ WHITE - RE D
-/ . }
BLACK
BL
AC K
((53
:/ __ J
q) ]
RED «BLACK A.
RED
CE
<
GR E EN
TACHOMETER ~ BLACK
lGROUND AT
-= ENGINE
BL UE
BLACK
CAPACIT OR
u
--l
ENGINE
HIRTH
793
I
I
-= IBLUE
~AR K PL U GS
I I - -~
I I
'cu' I _ _ J
BLACK
IGNITION COIL
II
~
."
::Itt
::::
c-:.
."
;a.
=
~
~
;;
fI