Gas Flows Out Exhaust On First Crank

I have a Craftsman Lawn Tractor with a Kohler CV492S engine. When I try to start it for the first time after sitting for a while (a few hours or till the next mowing) it will stop cranking before a full rotation, almost as if the piston jams at TDC, and then gas will flow down and out through the exhaust. No oil , pure gas.

I cannot turn it over while the gas is flowing (nor do I want to catch it on fire). Once the gas stops pouring out (several ounces), the tractor starts just fine and runs fine. There does not appear to be any gas in the oil. I do get an initial smoke plume now which I assume it the residual gas but no smoke during operations. If I turn it off and restart it in a relatively short period of time it starts no problem. If I leave it for a longer period then it happens. Again I have to wait for the gas to pour out and then it starts fine and runs fine.

I am assuming that somehow gas is slowly flowing into the piston through the intake valve when the engine is off. When I start it the first time, the exhaust valve open at TDC and pushes all the gas in the chamber out through the exhaust. The reason for the jamming would be the fluid filled chamber cannot compress properly.

Can anyone tell me if they know what may cause this experience, if my assumtions are correct, and what I need to do to correct it.

Thanx

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• Re: Gas Flows Out Exhaust On First Crank Joe Friday, May 09, 2008 (0)

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