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Broken piston rod questions.....

4808 Views 9 Replies 7 Participants Last post by  RoyM
I could use some help on this. As the title says, my 21hp Briggs tossed a rod and I'm trying to decide if it's worth fixing. It's one of those ohv Intek motors that I have read on here just aren't very good. The crank is gouged up pretty good where the rod used to connect. I don't want to buy a new crank. The cost is almost half a new crate motor. Is this something I could bring to a machine shop and have honed? If I do have it smoothed out how does this affect the rod where it attaches to the crank. I don't see any bearing in the part list. Is the connecting end of the rod adjustable? The piston and cylinder walls look fine. Is there anything else I should be looking for or replacing? In the last month the camshaft broke and now the piston rod. Are these common problems for these engines? I am not running it out of oil, so I am wondering if it's something else....head gasket? No loss of power.....but I'm losing parts at a pretty good clip......any advice?
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Per the Walter prices, low end would be about: $140 High: $240
Labor would then be added for removal, disassembly, cleaning, re-assembly, and installation if you don't do it yourself.
Most connecting rod failures are due to either lack of lubrication or exceeding recommended rpms. If the journal on the crankshaft was gouged rather than scored, it might be possible to remove the raised area around the gouge, leaving a small pit, and replace the connecting rod without having the journal turned to the next smaller undersize. The bearing on the big end of the connecting rod on most small engines is formed by the connecting rod material. There is no removable insert as used on auto & truck engines.
You might consider searching your local for-sale listings for a mower with another engine to replace yours. Sometimes mowers will have problems that make repair unattractive, while having an engine that is in good shape. Buy the mower, transplant the engine, feed the remains to a recycler or sell parts to help recover the cost.
I did not see a listing of deck size, but most 42" decks can be powered by lower horsepower engines with little problem. You can take a 7hp cut without problems, unless you are mowing very heavy growth.
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