6. What are the indications of a lean fuel mixture, and how does one correct it?

A lean fuel mixture is most often indicated by a hesitation during acceleration (in neutral or in forward). In more severe cases, the hesitation is sometimes accompanied by a "popping" sound from the intake throat of the carburetor; in more subtle cases, a lean condition may cause nothing more than a slight reduction in performance at high power settings.

If your engine has a late model (aluminum) carburetor, it will have a fixed main jet, and you won't be able to adjust the fuel mixture at cruising RPM. In this case, you will have to take the carburetor apart for cleaning - the problem is most likely a small restriction in the main jet.

If your engine has an early model carburetor, it will have an adjustable main jet with a small "T" handle extending out of the bottom of the carburetor at about a 45 degree angle. To make the engine run richer, you would turn the "T" handle counter-clockwise, as you would be facing the handle. The adjustment on the main jet is quite slow, so it may take at least half a turn before noticing any substantial difference. - Updated: January 4, 2004