I have a Scag mower with a Kohler 22 hp engine. It wouldn't start so I cleaned and rebuilt the carb. It started and ran fine for one week. Now if won't start, again. Did I not clean the carb well enough? The gas is fresh and the fuel filter is new. It is getting spark and gas.

Well, lets see, you need fuel, air and spark to get ignition. I'd be suspect of a float jam.

When you are trying to start the mower, do you see fuel or smell fuel leaking from the air cleaner.

You could be flooding the carb.

Don's taking you down the right road. Your rebuilding may be a bit off. Just take your bowl off and check that float and needle valve operation. Sometimes just checking a bowl will clear it of debris.

Don and ball are right on track here I think. One thing I do when I do a carb is clean the tank, and fuel lines, along with changing the filter. Just a microscopic particle can cause chaos for a small engine. And just because you have spark, fuel, air and compression doesn't mean that your engine will start. Sometimes the flywheel key can be sheared and you will have all the indications that it should start but the spark is not at the precise moment because of the key being sheared. Try the carb again, then check the flywheel's key.

Thanks, guys! I really appreciate your help. I will clean the carburetor again and flush the fuel tank and fuel lines. I think this will take care of the problem. If it doesn't, I will check the timing.