Troubleshooting a lawn tractor carburetor, or any small engine carburetor, usually requires checking the O-rings and adjustment screws for damage, adjusting the main mixture adjustment or idle mixture screws or checking for bent throttle plates or a bent choke. Troubleshooting depends on what is happening with the lawn tractor.
Before checking out the carburetor, be sure to disconnect the spark plugs and battery cables and always wear safety goggles and gloves. The following shows what to check when troubleshooting a malfunctioning carburetor.
- An engine that will not idle or one in which the idle speed is excessive may suffer from cracks. Check for cracks, and also check the nylon check ball for function, if the carburetor has one.
- If the carburetor is out of adjustment or the engine over idles, first take a look at the governor linkage and adjust as necessary.
- If the idle speed seems excessive most of the time, check to make sure the Welch plugs, gaskets and caps are seated firmly and not leaking.
- A carburetor that floods one minute and runs lean the next may have a damaged inlet needle. Be sure it is in good condition and properly positioned.
- If the engine refuses to start, try cleaning the carburetor after removing all non-metallic parts.
- If the carburetor does not work properly after a thorough cleaning, adjust the control cable to make sure the carburetor is achieving full choke.