2009 Polaris Sportsman 850 XP EFI EPS Service Manual, Page 72Get this manual
ELECTRONIC FUEL INJECTION FUEL SYSTEM TROUBLESHOOTING
The correct position of the throttle body stop screw is established and set at the factoryDO NOT remove the tamper proof cap to adjust the throttle body stop screw or alter its position in any mannerThe stop screw controls the air flow calibration of the throttle body
Poor Idle
Symptom: Idle Too High (If greater than 1400 RPM when engine is warm) Throttle stop screw tampering Throttle cable sticking, improperly adjusted, routed incorrectly Failed sensor or disconnected wiring IAC stuck or inoperative Intake air leak
Fuel StarvationLean Mixture
Symptoms: Hard start or no start, bog, backfire, popping through intakeexhaust, hesitation, detonation, low power, spark plug erosion, engine runs hot, surging, high idle, idle speed erratic No fuel in tank Restricted tank vent, or routed improperly Fuel lines or fuel injectors restricted Fuel pump inoperative Air leak in system Intake air leak (throttle shaft, intake boot, gasket or grommet) Throttle stop screw tampering Failed sensor or disconnected wiring