hydro-lock in a Kohler

Danl99

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I have a Lawnboy 10730, with a Kohler XT650 engine. Five years old. Seems to have developed hydro-lock, whereby I can't pull the starting cord. I remove the spark plug, and I can pull the cord fine fine (though nothing comes out of the plug hole - I would have expected some oil to shoot out). I replace the spark plug, and I can't pull the cord again. What's the fix???
 

Rivets

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If nothing comes out the cylinder with the spark plug out, I’d be looking at the valves. Remove the spark plug and valve cover. While rotating the flywheel by hand watch the valves to confirm they are opening. Let us know what you find.
 

Bertrrr

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Can you feel any compression when the plug is out and you pull the cord ? This will expose a lot
 

Danl99

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Thanks. I managed to get it started, and have wired the safety handle to keep it going for a while. Is that likely to eventually clear out the problem? It's running smoothly, with no smoke coming out.
 

Danl99

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Well, that's depressing. After getting it started, and letting it run smoothly for 15 minutes, when I try to start it back up, the hydra-lock is still there. You'd think that running it for a while would clear out any problem, but that's evidently not the case.
 

Bertrrr

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While it's locked as you say , pull your plug and use a straight rod and see what position the piston is in, Curious if it's BTC or TDC.
 

Danl99

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Not sure what that means. Please explain carefully. What do I do with a rod?
 

StarTech

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Does not sound hydrolock as the term indicates there must be a liquid involved. It more likely a mechanical failure such as the ignition being loose, engine brake not releasing, or internal problem.

BTW BDC is Bottom Dead Center and TDC is Top Dead Center. Both refers to the piston position.

As for the rod you would inserting it thru the plug hole to find where the piston is sitting in the cylinder.
 

Danl99

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But, as I said, I was able to get it to run, and it ran smoothly for 15 minutes. You'd think a mechanical failure wouldn't come and go, and specifically go away when I pull the spark plug. Tried that several times. Spark plug in, CAN'T pull cord. Spark plug out, CAN pull cord.
 
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