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Repair guides and support for riding, or ride-on, mowers, also known as lawn tractors, of all types used in tending large tracts of land.

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Why won't my mower start?

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?

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Have you taken your spark plug out and held it to the metal of the cylinder head to see if it got spark? Of course you do not want to hold it by hand. Wedge it somehow and see if you got spark. What type of engine do you have in there? what is the serial number? It is possible that this is either an ignition or a valve issue.

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I have checked for spark and it is getting it. The flooding is what I believe is halting the spark. Is the carburetor float bad?

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change your oil .....do you smell gas in the oil???

carb is leaking fuel into cylinder when shut off. inline shut off valve will cure that

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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.

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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?

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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

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bob will be eternally grateful.
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