50cc gy6 won’t start

[xAjX1994]

Hello, so I have a 50cc gy6 in my chuckus I bought and
When I go to start it it turns over and sometimes sounds
Like it’s goig to start but it doesn’t, has brand new
Carburetor , I did a compression test and got about
110psi, can someone please help thanks :)

[xAjX1994]

I believe I have found the issue, the woodruff key on my crankshaft has sheared off, is this fixable without replacing the whole crankshaft 😩😩

[Roscoe]

Sure it can be replaced. I'd want to know why it sheared, make sure the new key allows the flywheel to seat correctly tight on the crankshaft. The tapered fit between the flywheel and the crankshaft and the flywheel key shouldn't be shearing on a GY6, a lawnmower yes but not on a GY6.

[xAjX1994]

I don’t think I tightened the flywheel bolt enough
To be honest, but I’m not sure

[xAjX1994]

Any tips on how I can tighten the flywheel bolt better? How can I
Get the motor to not spin when tightening?

[neo71665]

Get about 10 feet of 1/4 inch rope.

Take the spark plug out, make sure the engine is at the bottom of the stroke, and now feed the rope in the plug hole until you can't fit any more. Now tighten the nut up. As the engine tries to rotate the rope will stop it. Once you are done working on it spin the engine backwards enough to remove the rope. Put the plug back in and go have fun.