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mtd 42" cut, briggs and stratton, hard to spin/start, tried adjusting valves

cc3337's Avatar

Join Date: Jan 2013
Posts: 8

02-27-14, 12:11 PM   #1  
mtd 42" cut, briggs and stratton, hard to spin/start, tried adjusting valves

i have an mtd 42" cut the mower will spin about a half turn, compression seems normal, i have looked at numerous how tos and videos of valve adjustment however i still cant make this motor spin no matter how many times i try adjusting valves, could this be any other problem, battery shows fully charged, thanks

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cheese's Avatar
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Join Date: Jul 2001
Posts: 16,570

02-27-14, 06:25 PM   #2  
Set both valves to .005" and if it will not turn, the battery and starter are good, there is no oil or gas in the cylinder, then the compression release on the camshaft is bad. You should be able to turn the flywheel and watch the bottom valve bump open just a hair right before the top of the compression stroke. If it is not doing this, the compression release on the camshaft broke. That's assuming you have an ohv single cylinder briggs engine, you didn't say.

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OptsyEagle's Avatar

Join Date: Dec 2006
Posts: 500

02-27-14, 06:30 PM   #3  
How's the battery? Have you recharged it?

I had a motor that would stop around the compression stroke that was flooding during storage. Gas was sneaking by the inlet valve of the carb and into the combustion chamber. Must have added a little hydrolocking resistance to go along with the compression stroke, stopping the crank.

To test this you could remove the spark plug and crank over the motor 10 or 15 times to blow out any liquid fuel. Reinstall the spark plug and try it quickly and see if she catches at all. If yours is flooding, installing a manual fuel shut off valve might fix it.

On a safety note. Keep in mind fuel might come out of the spark plug hole and you don't want a fire. Ground the spark plug boot would help. That's the only thought I have. I know nothing about starters.

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