# Tecumseh broken con rods -why?



## Rpeters123 (Oct 19, 2005)

Why goes wrong on the 7 and 8 HP snowblower engines that break connecting rods so often? Con rod bolts loosen up? oil dipper breaks off rod bolts? what do you find? Does just replacing the broken rod seem to work? Can hear rod knock before they throw a rod through side of block most time.


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## glenjudy (Aug 26, 2006)

Rods break in these small engines for several reasons, but most commonly when the rod siezes on the crank journal. It's, generally, always due to oil, i.e., low oil, no oil, contaminated oil, or wrong oil. Cold climates will require a 10w-30, or even a 5w-30, some weight with proper viscosity for when the engine is started cold at ambient tempature.
You can't just replace a rod. Well, you can, but it won't last long. To repair a broken rod due to siezing on the crank journal, you must grind journal to some undersize and match it to the corresponding size rod.
hope this helps.


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## Rpeters123 (Oct 19, 2005)

*no lack of oil in engine*

The crankshaft still lookd like new. Did not run low on oil. I think the con rods are weak or if you run the engine over 3600 RPM the rod streaches and then breaks. Does anyone find the con rod bolts get loose?


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## repair_guy (May 9, 2004)

That's when you find some way to lock the bolts in place,although 3600 RPM's is the lemit most small engines from 3 Hp. up to say 6 Hp.,anyway,are designed to go.


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