4-12
TESTING VACUUM
NOTE: Make sure adequate fuel is in the carburetor
for this test.
1. Connect Vacuum Test Pump directly to the fuel
pump inlet fitting.
2. With snowmobile on a safety stand, start the engine
and accelerate to 2000-3000 RPM for a period of 30
seconds. Note maximum reading of gauge. Reading
must be 7-10 in.-hg.
3. Stop engine. Connect fuel hose. Turn the shut-off
valve to the OPEN position.
Troubleshooting
Problem: Carburetor Too Rich (0-1/4 Opening)
Condition
Remedy
1.
Choke plunger
will not seat
2.
Pilot air screw
too far in
3.
Pilot air passage
obstructed - damaged
4.
Float/inlet needle
obstructed - damaged - adjusted incorrectly
5.
Pilot jet
loose
1. Adjust - service - replace choke cable - plunger assembly
2. Adjust pilot air screw
3. Remove obstruction - replace pilot air screw - carburetor
4. Remove obstruction - replace inlet needle - float - adjust float tab
5. Tighten pilot jet
Problem: Carburetor Too Rich (1/4-3/4 Opening)
Condition
Remedy
1.
Pilot air screw
too far in
2.
Needle jet needle
worn - adjusted incorrectly - incorrect
3.
Pilot air passage
obstructed - damaged
4.
Pilot jet
loose
5.
Float/inlet needle
obstructed - damaged - adjusted incorrectly
6.
Main jet
loose - too large
7.
Primary air passage
obstructed
1. Adjust pilot air screw
2. Replace needle jet - replace - adjust jet needle E-clip
3. Remove obstruction - replace pilot air screw - carburetor
4. Tighten pilot jet
5. Remove obstruction - replace inlet needle - float - adjust float tab
6. Tighten - replace main jet
7. Remove obstruction
Problem: Carburetor Too Rich (3/4-WOT Opening)
Condition
Remedy
1.
Main jet
loose - too large
2.
Float/inlet needle
obstructed - damaged - adjusted incorrectly
3.
Needle jet needle
worn - adjusted incorrectly - incorrect
1. Tighten - replace with smaller main jet
2. Remove obstruction - replace inlet needle - float - adjust float tab
3. Replace needle jet - replace - adjust jet needle E-clip
Problem: Carburetor Too Lean (0-1/4 Opening)
Condition
Remedy
1.
Choke plunger
remains seated
2.
Pilot air screw
too far out - damaged
3.
Piston valve
sticks open - damaged - worn
4.
Pilot jet - outlet
obstructed
5.
Float/inlet needle
obstructed - damaged - adjusted incorrectly
1. Adjust - service choke cable - plunger assembly
2. Adjust - replace pilot air screw
3. Service - replace piston valve - throttle cable - spring
4. Remove obstruction
5. Remove obstruction - replace inlet needle - float - adjust float tab
Problem: Carburetor Too Lean (1/4-3/4 Opening)
Condition
Remedy
1.
Pilot air screw
too far out - damaged
2.
Needle jet
obstructed
3.
Pilot jet - outlet - main jet
obstructed
4.
Float/inlet needle
obstructed - damaged - adjusted incorrectly
5.
Jet needle E-clip
position
incorrect
1. Adjust - replace pilot air screw
2. Remove obstruction
3. Remove obstruction
4. Remove obstruction - replace inlet needle - float - adjust float tab
5. Adjust E-clip
Problem: Carburetor Too Lean (3/4-WOT Opening)
Condition
Remedy
1.
Main jet
obstructed - too small
2.
Float/inlet needle
obstructed - damaged - adjusted incorrectly
3.
Needle jet needle
obstructed
1. Remove obstruction - replace with larger main jet
2. Remove obstruction - replace inlet needle - float - adjust float tab
3. Remove obstruction
Problem: General Fuel System (Engine Cuts Out at High RPM)
Condition
Remedy
1.
Fuel delivery
inadequate
2.
In-line fuel filter
obstructed - damaged
3.
Gasoline
contaminated
4.
Gas-tank vent - hose
obstructed
1. Repair - replace fuel pump - impulse hose
2. Remove obstruction - replace in-line fuel filter
3. Replace gasoline - de-ice - clean carburetors
4. Remove obstruction - replace vent - hose
Problem: General Fuel System (One Cylinder Runs Lean)
Condition
Remedy
1.
Carburetor-to-cylinder
air leak
2.
Carburetors
not aligned vertically
3.
Primary compression (crankcase)
low
4.
Carburetors
not synchronized
1. Repair/replace gaskets/flanges - service intake ports - tighten
clamps
2. Align carburetors vertically
3. Troubleshoot engine
4. Synchronize carburetors
Summary of Contents for Sno Pro 120
Page 20: ...1 18 NOTES ...
Page 29: ...2 9 2 570ENG12 ...
Page 39: ...2 19 2 500CC2A_12 ...
Page 45: ...2 25 2 NOTES ...
Page 47: ...2 27 2 800_12_2 ...
Page 61: ...2 41 2 Engine Torque Patterns 1100 cc 1100TorquePattern12 ...
Page 63: ...2 43 2 1100ccZ1RV10 ...
Page 81: ...2 61 2 1100ccZ1RV10 ...
Page 82: ...2 62 Engine Torque Patterns 1100 cc 1100TorquePattern12 ...
Page 141: ...2 121 2 SNO2152 ...
Page 142: ...2 122 SNO2153 ...
Page 180: ...3 18 0742 314 0746 520 F5 LXR 800 cc ...
Page 204: ...3 42 NOTES ...
Page 260: ...5 26 Troubleshooting Servomotor SERVO1A12 ...
Page 261: ...5 5 27 SERVO2rv ...
Page 264: ...Magneto 0746 255 1 ...
Page 266: ...Main Harness p n 1686 603 F5 LXR 0746 249 3 ...
Page 269: ...Main Harness p n 1686 588 F 800 M 800 XF 800 0746 242 6 ...
Page 270: ...Main Harness p n 1686 611 TZ1 Turbo LXR LTD 0746 253 7 ...
Page 271: ...Main Harness p n 1686 610 TZ1 TZ1 LXR 0746 252 8 ...
Page 272: ...Main Harness p n 1686 613 Bearcat Z1 XT GS p n 1686 615 Bearcat Z1 XT LTD 0746 511 9 ...
Page 273: ...Main Harness p n 1686 578 Sno Pro 120 10 0744 204 ...
Page 274: ...Ignition Main Harness p n 1686 628 Sno Pro 500 11 0745 605 ...
Page 275: ...Ignition Main Harness p n 1686 657 Sno Pro 600 12 0746 250 ...
Page 276: ...0745 601 13 Console Harness p n 1686 631 TZ1 LXR TZ1 Turbo LXR LTD ...
Page 277: ...Hood Harness p n 1686 638 F 800 M 800 XF 800 0746 243 14 ...
Page 278: ...Console Harness p n 1686 633 Bearcat 570 F570 T570 0746 238 15 ...
Page 279: ...Console Harness p n 1686 634 F5 LXR 0746 240 16 ...
Page 280: ...Hood Harness p n 1686 639 F 1100 Turbo M 1100 Turbo HCR XF 1100 Turbo 0746 246 17 ...
Page 282: ...0746 254 19 Console Harness p n 1686 547 Bearcat Z1 XT GS p n 1686 549 Bearcat Z1 XT LTD TZ1 ...
Page 283: ...Hood Harness p n 1686 587 Sno Pro 500 20 0744 201 ...
Page 285: ...Passenger Seat Harness p n 1686 570 22 0744 197 ...
Page 286: ...Handlebar Harness p n 1686 636 F 800 M 800 XF 800 p n 1686 654 M 800 HCR 0746 244 23 ...
Page 287: ...Handlebar Harness p n 1686 537 Bearcat 570 F570 T570 0746 239 24 ...
Page 288: ...Handlebar Harness p n 1686 574 F5 LXR 0744 189 25 ...
Page 289: ...Handlebar Harness p n 1686 637 F 1100 Turbo M 1100 Turbo XF 1100 Turbo 0746 247 26 ...
Page 290: ...Handlebar Harness p n 1686 590 Sno Pro 500 27 0744 200 ...
Page 291: ...Handlebar Harness p n 1686 656 M 1100 Turbo Sno Pro HCR 28 0746 510 ...
Page 292: ...Misc Groomer Special p n 1686 645 p n 1686 646 p n 1686 647 p n 1686 648 29 0746 241 ...
Page 460: ...8 26 0744 930 ...