Spark Plug Fouling; Cooling Troubleshooting - Polaris Ranger 500 2x4 2007 Service Manual

Backfiring
• ETC or speed limiter system malfunction
• Fouled spark plug or incorrect plug or plug gap
• Carburetion faulty - lean condition
• Exhaust system air leaks
• Ignition system faulty:
Spark plug cap cracked/broken
Ignition coil faulty
Ignition or kill switch circuit faulty
Ignition timing incorrect
Sheared flywheel key
• Poor connections in ignition system
• System wiring wet
• Valve sticking
• Air leaks in intake
• Lean condition

Spark Plug Fouling

• Spark plug cap loose or faulty
• Choke cable adjustment or plunger/cable sticking
• Foreign material on choke plunger seat or plunger
• Incorrect spark plug heat range or gap
• Carburetor inlet needle and seat worn
• Jet needle and/or needle jet worn or improperly
adjusted
• Excessive carburetor vibration (loose or missing needle
jet locating pins)
• Loose jets in carburetor or calibration incorrect for
altitude/temperature
• Incorrect float level setting
• PVT system calibrated incorrectly or components worn
or mis-adjusted
• Fuel quality poor (old) or octane too high
• Low compression
• Restricted exhaust
• Weak ignition (loose coil ground, faulty coil, stator, or
ETC switch)
• ETC switch mis-adjusted
• Restricted air filter (main or pre-cleaner) or breather
system
• Improperly assembled air intake system
• Restricted engine breather system
• Oil contaminated with fuel
• Restricted oil tank vent

Cooling Troubleshooting

Overheating
• Low coolant level
• Air in cooling system
• Wrong type of coolant
• Faulty pressure cap or system leaks
• Restricted system (mud or debris in radiator fins or
restriction to air flow, passages blocked in radiator,
lines, pump, or water jacket)
• Lean mixture (restricted jets, vents, fuel pump or fuel
valve)
• Fuel pump output weak
• Restricted radiator (internally or cooling fins)
• Water pump failure
• Cooling system restriction
• Cooling fan inoperative or turning too slowly (perform
current draw test)
• Ignition timing misadjusted
• Low oil level
• Spark plug incorrect heat range
• Faulty hot light circuit
• Thermostat stuck closed or not opening completely
Temperature Too Low
• Thermostat stuck open
Leak at Water Pump Weep Hole
• Faulty water pump mechanical seal (coolant leak)
• Faulty pump shaft oil seal (oil leak)
ENGINE
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