# Need advice on replacing a B&S 17.5HP engine



## JoeW (Mar 31, 2007)

My son was using our Craftsman LT1000 riding mower, not aware that the drain plug was loose. It didn't take long before it ran out of oil and the engine blew.

I took the engine to my local small engine shop, and he recommended buying a new engine, instead of rebuilding mine.

So I'm looking for a good replacement for my Briggs & Stratton 31c707-0230e1 engine, and it appears my old engine is no longer available.

My biggest concern it spending the ~$500 for a new engine, and then have to retrofit something, or getting an engine with the wrong size shaft, mounting holes being different, etc.

I've found what I _think_ would be suitable replacements, but I'm still a little unsure (31N707-0026, 31G777-0036, 31G707-0026, and the 31P777-0602).

Can any of you offer some advice on a good replacement engine? Any gotchas I should look out for?

My wife suggested just going out and spending $1200 on a new riding mower. But I'm determined to find a good replacement engine for this thing. Disposable computer printers and VCRs is one thing, but I draw the line at treating a *riding mower * as "disposable" as soon as something breaks on it!

Thanks for any help you can provide!
Joe


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## 30yearTech (Sep 14, 2006)

There is a replacement engine available 31c707-0230-E2 but the list price on this engine is pretty high, I would probably replace the entire unit before spending over a grand for this engine.

You might want to consider a short block Part number: 697761 lists for $359.06 if all your bolt on parts are still in good shape (i.e. carburetor, muffler, magneto etc...) then this would give you a new block and all internals at a reasonable price if you can do the labor yourself.

The engines you listed will most likely work in your application, the main differences may be with the wiring harness, muffler and throttle cable hook up to your current configuration. Most riding mowers have a 1" diameter crankshaft 3 5/32" long with a 1/4" keyway and drilled and tapped for a 7/16" mtg bolt. The bolt pattern on the engine sump should match up alright that is fairly standard.


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## oscaryu1 (Mar 25, 2007)

it shouldnt be much to replace the rod should it? or did it crack the piston too? crankshaft? or just buy a 12 hp or less


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## JoeW (Mar 31, 2007)

My lawn is slightly rolling. A 12 horse wouldn't be up to it.

As for the piston, yes, it seems to be broken. I'll take it apart eventually, just because I'm curious. 

I think I'm going to order a 31P777-0602 engine. It appears to have the same bolt hole placement, the same shaft dimensions (same shaft part # even), and offers an oil filter and an extra half-horse to boot. I imagine I looked pretty strange out there with 17 and A HALF horses. Now I'll have an even 18. 

Thanks for the replies!
Joe


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## oscaryu1 (Mar 25, 2007)

good luck !  :thumbsup: taking apart my first engine got me into studying ~


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