Yes you can

I own lathes and mills (check the sig) And the flywheels on some of these little engines aren't even drill on center. If you are careful, you can cut the fins off with side cutters, and file them smooth. Just don't cut into the main body of the flywheel. If you have a prop balancer, you can re check it… otherwise, you should be fine. Remember… you will be spinning this engine slower than it would have in the weedeater. And, the engine isn’t balanced internally perfectly anyway.

I’m sure I’ll start a fight over what I just said… but you will be fine for a low output engine. If you were looking to spin it 10K rpm’s or higher… I would tell you a different story.

Good luck