BOOM!

Hammermechanicman

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9 year old mower came in for bad drive belt and broken hydro fan. Easy fix. Never touched the engine. Fixed the belt and fan and sharpened the blades. Fired it up and mowed for about a minute and BOOM. Rod, piston and gasket kit $150 and labor. Charged her for the belt and fan and i ate the rest. Some you win and some you lose.

And yes it had oil in it. The bore was fine and the rod didn't seize on the crank.
 
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ILENGINE

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Did you find cause of failure. Would be nice to see the rest of the broken pieces.
 

Hammermechanicman

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Did you find cause of failure. Would be nice to see the rest of the broken pieces.
No. Didn't seem to over rev.
Already tossed the rod. There was probably 30 small pieces of rod material. Engine was a 31R777. Lucky it didn't break the block. Did shear the key. I used a 240 grit ball hone to break the glaze and had to file and smooth a ding in the crank journal. Could have been worse.
 

ILENGINE

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The rod bearing shows a slight hint of aluminum smear combined with carbonized oil deposits. Don't know if it was enough to cause a loose rod bolt which would of lead to the failure. I think the piston damage is secondary due to the piston canting in the bore after the initial break.
 

Hammermechanicman

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I assumed the rod seized but there was absolutely no aluminum on the crank. Yeah i think the piston got taken out because of the rod.
Interesting, the parts list shows 2 different pistons depending on date code. Either one works. Only difference is one uses 2 wrist pin clips and the other only 1.
 

StarTech

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You can go broke covering things like this. If not told about the equipment previous problems and the it fails during testing I still charge the customer. I don't try make the customer for a failure that is out of my control. It would had failed if the you didn't test the mower with the customer using it and they would blame you not matter what just to get out paying for the repairs.
 
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