Polaris 2015 RZR 900 Service Manual page 154

ENGINE / COOLING SYSTEM
• Cylinder head gasket leak
• No valve clearance (cam wear)
• Cylinder or piston worn
• Piston rings worn, leaking, broken, or sticking
• Bent valve or stuck valve
• Valve spring broken or weak
• Valve not seating properly (bent or carbon
accumulated on sealing surface)
• Rocker arm sticking
Backfiring
• Fouled spark plug or incorrect plug or plug gap
• Intake system air leaks
• Exhaust system air leaks
• Valve sticking
• Ignition system faulty:
• Spark plug cap cracked / broken
• Ignition coil faulty
• Ignition or kill switch circuit faulty
• Poor connections in ignition system
• Ignition timing incorrect
• Sheared flywheel key
Overheating
• Low coolant level
• Air in cooling system
• Wrong type/mix of coolant
• Faulty pressure cap or system leaks
• Restricted system (mud or debris in radiator fins
causing restriction to air flow, passages blocked in
radiator, lines, pump, or water jacket, accident
damage)
• Lean mixture (vents, fuel pump or fuel valve)
• Fuel pump output weak
• Electrical malfunction
• Water pump failure/ Loose impeller
• Thermistor failure
• Cooling fan inoperative or turning too slowly
(perform current draw test)
• Low oil level
• Spark plug incorrect heat range
• Faulty hot light circuit
3.88
• Thermostat
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)
9925723 R01 - 2015 RZR 900 Service Manual
© Copyright 2014 Polaris Industries Inc.
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