Do You Have the Correct Jet Size?
To determine if you need to change the jets, look at the spark plugs.
Plugs should be gray or tan color.
White indicates a lean condition. Increase the jet size by .002 and try again. Note: A vacuum leak can also cause this condition.
Black indicates a rich condition. Decrease the jet size by .002 and try again. Note: Ignition problems can also cause this condition.
Altitudes above 5,000 feet usually require lowering jet sizes by .002.