Page 314 - Manual Oficina Polaris Sportsman 570 2014 a 2016

ENGINE / COOLING SYSTEM

TROUBLESHOOTING • Dirt entering engine through cracks in air filter or ducts
• Engine oil dirty or contaminated
ENGINE
Excessive Smoke and Carbon Buildup
Spark Plug Fouling • Excessive piston-to-cylinder clearance
• Spark plug cap loose or faulty • Worn rings, piston, or cylinder
• Incorrect spark plug heat range or gap • Worn valve guides or seals
• PVTsystem calibrated incorrectly/ components worn • Restricted breather
or mis-adjusted • Air filter dirty or contaminated
• Fuel quality poor (old) or octane too high
• Low compression Piston Failure - Scoring
• Restricted exhaust • Lack of lubrication
• Weak ignition (loose coil ground, faulty coil, or stator) • Dirt entering engine through cracks in air filter or ducts
• Restricted air filter (main or pre-cleaner) or breather • Engine oil dirty or contaminated
system
• Improperly assembled air intake system Slow Engine Cranking
• Restricted engine breather system • Weak battery
• Oil contaminated with fuel • Loose Electrical connections
• Decompression Mechanism not functioning properly.
Engine Turns Over But Fails To Start
• No fuel Excessive Smoke and Carbon Buildup
• Dirt in fuel line or filter • Excessive piston-to-cylinder clearance
• Fuel will not pass through fuel valve • Wet sumping due to over-full crankcase
• Fuel pump inoperative/restricted • Worn rings, piston, or cylinder
• Tank vent plugged or pinched • Worn valve guides or seals
• Engine flooded • Restricted breather
• Low compression (high cylinder leakage) • Air filter dirty or contaminated
• No spark (Spark plug fouled) ignition component
failure Low Compression
• Cylinder head gasket leak
Engine Does Not Turn Over
• No valve clearance (cam wear)
• Dead battery • Cylinder or piston worn
• Starter motor does not turn • Piston rings worn, leaking, broken, or sticking
• Engine seized, rusted, or mechanical failure • Bent valve or stuck valve
• Valve spring broken or weak
Engine Runs But Will Not Idle
• Valve not seating properly (bent or carbon accumu-
• Restricted fuel supply lated on sealing surface)
• Low compression • Rocker arm sticking
• Crankcase breather restricted
Backfiring
Engine Idles But Will Not Accelerate • Fouled spark plug or incorrect plug or plug gap
• Spark plug fouled/weak spark • Exhaust system air leaks
• Broken throttle cable • Valve sticking
• Obstruction in air intake • Ignition system faulty:
• Air box removed (reinstall all intake components) • Spark plug cap cracked / broken
• Incorrect flywheel installation or sheared flywheel key. • Ignition coil faulty
• Restricted exhaust system • Ignition or kill switch circuit faulty
• Cam worn excessively • Poor connections in ignition system
• Ignition timing incorrect
Engine Has Low Power • Sheared flywheel key
• Spark plug fouled
• Cylinder, piston, ring, or valve wear or damage (check
compression)
• PVT not operating properly
• Restricted exhaust muffler
• Cam worn excessively
Piston Failure - Scoring
• Lack of lubrication

3.192 9926803 R06 - 2014-2016 Sportsman 325 / ETX / 450 HO / 570 Service Manual
© Copyright Polaris Industries Inc.