Yamaha RST90G Owner's Manual page 112

Troubleshooting
 Seized engine: Seizure is caused by poor
lubrication, inadequate fuel, or an air leak.
Ask a Yamaha dealer to check.
 RST90: "Hydrostatic lock" occurs when
fuel has filled cylinders during transporta-
tion of vehicle: Remove spark plugs and
turn engine over several times with ignition
off to expel excess fuel. Ask a Yamaha
dealer to check.
Engine power is low
 Low coolant temperature indicator light is
flashing: Warm engine up.
 Faulty spark plugs: Clean or replace spark
plugs.
 RST90: Incorrect carburetor jetting for alti-
tude or temperature: Ask a Yamaha dealer
to check.
 Improper fuel flow: See "Engine turns over
but does not start–Fuel system" above.
 Incorrect V-belt clutch settings for altitude
or conditions: Ask a Yamaha dealer to
check.
Engine constantly backfires or mis-
fires
 Faulty spark plugs: Replace spark plugs.
 Clogged fuel system: See "Engine turns
over but does not start–Fuel system"
above.
 Malfunctioning T.O.R.S.: See "Engine turns
over but does not start–Electrical system"
above.
Engine overheats
 Insufficient coolant: Add coolant.
 Air in cooling system: Bleed cooling system
or ask a Yamaha dealer to check.
 Leaking coolant: Ask a Yamaha dealer to
check.
Snowmobile does not move
 Malfunctioning
Yamaha dealer to check.
106
V-belt clutch: Ask
 Drive track does not move: Foreign object
is caught in drive track, or slide runners
have melted to slide metal due to lack of lu-
brication.
 Tight, loose, or broken drive chain: Ask a
Yamaha dealer to check.
V-belt twists
 Improper V-belt: Replace with correct V-
belt.
 Incorrect V-belt clutch offset: Ask a
Yamaha dealer to check.
 Loose or broken engine mount(s): Ask a
Yamaha dealer to check.
V-belt slips or becomes extremely hot
 Oily or dirty V-belt or primary and second-
ary sheave assembly surfaces: Clean.
 Problem with driveline: See "V-belt twists"
above.
Engine does not upshift or downshift
properly or engages harshly
 Worn or damaged V-belt: Replace V-belt or
ask a Yamaha dealer to check.
 Incorrect V-belt clutch settings for altitude
or conditions: Ask a Yamaha dealer to
check.
 Worn or sticking primary sheave assembly:
Ask a Yamaha dealer to check.
 Worn or sticking secondary sheave assem-
bly: Ask a Yamaha dealer to check.
Noise or excessive vibration in drive
chain and sprockets
 Broken V-belt clutch components: Ask a
Yamaha dealer to check.
 Worn or damaged bearings: Ask a Yamaha
dealer to check.
 Worn or damaged V-belt with flat spots:
Replace.
 Worn or damaged idler wheels or shafts:
a Ask a Yamaha dealer to check.