Polaris Outlaw 9921123 Owner's Manual page 196

Engine Backfires
Possible Cause
Weak, fouled or defective spark plug
Incorrect spark plug gap or heat range
Old or non-recommended fuel
Exhaust leak
Incorrectly installed spark plug wire
Incorrect ignition timing
Mechanical failure
Solution
Inspect, clean and/or replace spark plugs
Set gap to specs or replace plugs
Replace with new fuel
Inspect system for leaks; see your Polaris dealer
See your Polaris dealer
See your Polaris dealer
See your Polaris dealer
Troubleshooting
193