Poor quality or low octane fuel
Replace with recommended fuel
Incorrect ignition timing
Incorrect spark plug gap or heat range
Set gap to specs or replace plugs
Engine Runs Irregularly, Stalls or Misfires
Fouled or defective spark plugs
Inspect, clean and/or replace spark
plugs
Worn or defective spark plug wires
Incorrect spark plug gap or heat
range
Set gap to specs or replace plugs
Loose ignition connections
Check all connections and tighten
Recharge battery to 12.8 VDC
Kinked or plugged fuel tank vent line
Replace with recommended fuel
Inspect and clean or replace
Electronic throttle control malfunction
Add or change fuel, clean the fuel
system
Replace with recommended fuel
Replace with recommended fuel
Replace with lower octane fuel
Inspect, clean and/or replace spark
plugs
Stopping/starting without adequate
Warm-up
Allow engine to warm up before
operating and/or stopping
Replace with recommended fuel
Inspect and clean or replace