Engine Repair Question

Old 07-24-03, 09:26 PM
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mower problem found...now what

I have a briggs 3.5 hp about 5 years old. when pulling the cord the fly wheel would just spin. I took the whole thing apart and the piston arm was shattered at the point it connected on the crank shaft. I want to buy a new piston arm and put it back to gether and see if it runs. there is a small nick at the bottom of the cylinder. can I get the piston arm and how the heck does the old one come off? also can i run it with the small nick if i file it down a little. I am not looking to cut grass or anything I just want to see if I can get it going (bought a new mower 2 years ago) I am interested in automotive as a hobby and thought id start with this mower. any help would be apreciated.
Old 07-25-03, 12:48 PM
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You can order parts for your mower engine at:


Holy crap I didn't think the link was that long.

This will take you to the page where you can enter the part number you need.

First things first, you need to find the model, type and code numbers on your engine. (Usually on the shroud near the spark plug) Then you can go to the B&S site and get the parts manual for your engine. You're supposed to need to pay 2 bucks to get the full size manual, but they offer a small version for free viewing.... which you can then either save or email to yourself for full size viewing and printing.

From there you can get the part number and check the price at the link I provided. I found that parts for these engines was not as cheap as I expected.

Also.... once you've learned for a while on these engines, be ready for a whole new world when you go automotive. They are different in complexity and size (of course).

Good luck and keep us posted.
Old 07-25-03, 05:33 PM
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Hello drace!

You can replace the piston rod, but you may need more than just that. Generally a set of rings would be installed any time the piston gets removed. Also, if the crankshaft looks scratched and galled where the connecting rod attatches to it, it will have to be repaired or replaced. Also check around on the crankcase for cracks or holes. Often times when a connecting rod breaks, it jabs a hole in the side of the block, rendering it useless.

The old piece of rod is removeable from the crankshaft by removing the two bolts that hold it on, and the end connected to the piston is removed by taking out the retainer rings at the wrist pin, slide the wrist pin out, and the rod comes off.
Old 07-25-03, 10:54 PM
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thanks for your help

I am gonna check it out and hopefully get it going I will let you guys know.
Old 07-26-03, 02:32 PM
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help with crankshaft

how can I get the crank shaft out of a briggs 3.5 horse. I already cracked the sump nothing serious only on the part that mounts to the mower. but the crank is still stuck, almost out. what next??
Old 07-26-03, 05:50 PM
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Hello: drace600

Web Hosts Note:
This thread has been merged with the original first question.

Requesting a small favor please. Kindly use the reply button to update this question, ask additional questions or add additional information to this original question, as long as it pertains to this engine.

In doing so it keeps all the threads together making it much easier for the professionals in the forum to keep track & reply back. Likewise for the other members and guests reading the question. Thanks.
Old 07-26-03, 06:27 PM
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thanks for letting me know

I will use the reply as I will be back with more on this engine, I got the crank shaft out with a wheel puller. now I wait and see. im gonna get a new connecting rod and put it all back to gether with a gasket kit my biggest concern is getting the crank shaft back through the hole in the bottom of the motor.
Old 07-27-03, 12:26 AM
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You shouldn't use, or have to use a puller to get the crankshaft out. If it is hard to remove, then there is probably dirt and rust on the shaft keeping it from sliding out. Clean it off to the bare metal to reinstall it and hope you didn't damage the bearing surface in the sump cover when you pulled it off. If it still won't go easily upon reinstallation, you either have a galled bearing or a bent crankshaft.

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