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Sumthin broke in old 12HP Kohler

guy48065's Avatar

Join Date: Nov 2007
Posts: 2,407

08-15-13, 09:13 AM   #1  
Sumthin broke in old 12HP Kohler

Yesterday I'm laying in my driveway changing my oil & I hear my neighbor try again & again to start his riding mower. It sounds to me like the starter is free spinning so I walk over. Turns out the flywheel is spinning but way too freely--no compression. Pull the plug & can only see the top of one valve--but at least it's working. No puff coming out the plug hole or the muffler. Pull the head & verify the piston isn't moving. I should say this is an old Wheel Horse mower with cast iron splash lubricated 12HP Kohler.

I'm told it simply quit while mowing with no warning or other symptoms. The part I'm puzzled about is how the crank can spin and not hit anything. The piston is halfway down the cylinder & if I nudge it a little further it does get bumped by the crank.

From this description what am I (or more likely HE) going to find when the case is separated?

The only thing (to me) that explains the crank spinning without knocking from a flailing broke rod is if the rod cap broke off. At this point I'm just curious.

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aka pedro's Avatar

Join Date: Jan 2013
Posts: 1,335

08-15-13, 10:08 AM   #2  
Sounds like you have it nailed.

cheese's Avatar
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Join Date: Jul 2001
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08-15-13, 07:42 PM   #3  
I'd think the same thing, it probably broke near the crank end of the rod.

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