Briggs 8 hp - pull start kicks back some of the time

anonymouse

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I have a Briggs and Stratton 8 horsepower engine (model 190432-6117-01), with very strange behavior.

The engine is from a chipper shredder, and I recently removed the impeller from the crankshaft. I screwed in a bolt which pushed on the crankshaft in a clockwise direction, and I encountered resistance when pushing in that direction, which allowed me to remove the impeller. I fear that this may have caused my issue.

After removing the impeller, the first time I attempted to start the engine, it started and ran OK (with choke on, at least). The second time, the pull start spun freely and didn't even catch on the flywheel at first. It took a lot of pulls, but it eventually caught on the flywheel. Once it did, I pulled on it, but the cord stopped turning mid-pull and pulled back in - not hard enough to pull it out of my hand (as some other people have complained about), and not all the way back in. I didn't hear it fire or anything - the rope just pulled back. I turned the switch to the off position (killing the spark), and the engine spun freely without kicking back.

I did some research, and apparently, this problem is mostly caused by a sheared flywheel key. So I partly disassembled the engine to have a look at the key.
I don't have a flywheel puller, so I didn't remove the flywheel, but from what I could see, the flywheel key looked OK. (Sidenote: There are no problems with the recoil starter - it spins fine.)
So I reassembled the engine and tried to start it again. The same thing happened - the first time, it ran, albeit badly and only for about five seconds until it shut off; the second time, the pull start failed to catch on the flywheel at first, but once it did, it kicked back.

I also heard that some other things might cause the problem, like improper valve adjustment and hydro-lock, but these things seem implausible, as the engine ran fine before I removed the impeller. Maybe the engine simply doesn't have enough momentum to spin over without that heavy impeller on the end of the crankshaft, so it just spins backward unless I pull hard enough.

Any help or advice would be appreciated.
 
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bertsmobile1

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Some engines require a load on them to provide enough inertia to overcome compression.
Without this the pull start needs to provide all of the energy which many can not.
Take the blade off most push mowers and you can not start them.

All this is because some of the engines have very light flywheels.

As for the pull start not engaging, they do wear so might need to be pulled off to check the action of the engagement pawls.
 
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