Originally Posted by Agreen
Maybe the cup is out of balance? You can try to test that by using one of those lawnmower blade balancing rigs or maybe make something similar. Just some way of telling if one side is heavier than the other. Then, like balancing a turbocharger, grind off some of the metal on the heavy spots to balance it out.
Otherwise, it may just have been another bad bearing. It's probably not a lubrication issue since it's only been the one bearing that has failed... twice. It may not even be an issue with the pull start. Maybe the crank isn't true, or the case isn't aligned.
Whatever you find, please update this thread. I'm intrigued now. I have a pull start and centrifugal clutch, so if that leads to premature bearing failure I'd like to know!
It's a good possibility my crank is imperfect. It is an older bolt on weight crank. Somewhere I have one of those blade balance things, I usually just use a nail in a vice so it is at the bottom of a toolbox somewhere.
Do you use the pullstarter with the fingers on the crank cup or the one with the fingers on the pullstart end?
I have both types but got them used in a box full of stuff some years ago at a garage sale. Never tried the latter one as it had a recoil problem from previous owner.
I'll let you know what I find.