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My 14.5 horse MTD lawn tractor puffs gas vapor out of the carburetor when I crank it over in attempt to start it up. It is getting compression and obviously air/fuel mixture which just leaves spark. If I choke it while cranking it, I will occasionally get a pop and nothing else. the spark plug was wet with gas as if it was flooded. Why won’t it start? Is the carburetor in need of an overhaul?
The wet plug means your fuel to air mixture is to rich (too much fuel and too little air), meaning that you are getting an incomplete burn of the fuel drawn into the cylinder for each cycle. It could also mean that you are not getting a hot enough spark (to ignite the mixture) thus leaving too much of the fuel unburned. You might also check to see if the exhaust is blocked.
bob, may be not bad but definitely out of adjustment and possible a stuck float. Remove the float bowl, clean it. Remove the needle valve and clean it too. Make sure that the float will close the needle valve when moved upward. Update It is getting enough spark, it is just flooding. Is the carburetor bad?
put an inline shut off valve in your gas line going into the carb. Turn it off at the end of your mowing and let it go dead on its own. your carb is one that is bad about leaking fuel into cylinder even when not running. the shut off valve will prevent that . turn on valve before cranking for your next trip around the yard. good luck
