A: There is no “pre-determined” combination of rods and jets for any given motor, accept for altitude corrective applications, which is 4% for every 3,000 ft of elevation. Every engine is going to require a different fuel curve. The best thing to do is run the carburetor on the engine right out of the box to build a baseline, then check the spark plugs and see how they look. You need to have a li...

A: This may be caused by a rip or tear in a base gasket, air horn gasket, or adapter gasket or some foreign material stuck in an air passage of the carburetor. Inspect the gaskets to make sure you have no vacuum leaks of any kind. Check to make sure carburetor is seated correctly, and is fastened with the correct hardware. You can perform a quick check to find external vacuum leaks (such as a leak...

A: First off, make sure the correct size, (cfm) carburetor is installed on the engine and be sure the idle mixture screws are properly adjusted (see page 6 of the Owner's Manual). You can always make your carburetor leaner, but this will not always improve gas mileage. Since every engine is different, there is no way of knowing how much of an affect leaning down the carburetor will have on your e...