Loose Flywheel Nut on DB30R Stock 97cc Engine

My pull start is out of commission and while waiting on the new assembly to arrive, I tried starting the engine using a cordless drill and 11/16 socket. The engine started up, but the nut on the impeller loosened up and caused the impeller to fall off while the engine was running. I tried tightening the flywheel nut back down, but the rotation from the running engine seems to keep causing the nut to loosen, causing the impeller to keep falling off.

Am I missing something here, like a lock washer, snap ring, loctite to keep that nut from spinning off? How do I keep that sucker from backing off??

Thanks in advance.
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Active Member
Just use the torque specs listed for your motor & use a torque wrench to lock it down properly. That should be enough to keep it there, assuming there isn't something else wrong (timing key, shaft, nut, etc).
The back of the nut was worn down, so I ended up putting a lock washer behind it and torqued it down. I don't think it is going anywhere now. The head of my cordless drill fell off trying to get the engine started because the flywheel spins backwards when trying to start the engine. It will start for about 5 seconds and then die. I was never able to get it to idle, so I am going to try and clean out the carb better and then wait for the new pull start assembly to get here.