A good half inch impact at a 120 psi will take that right off, hold the flywheel by hand with a rag. Hold on to it like a man or you will spin the crank and beat the s**t out of the cases with the rod and ruin the engine. And yes I said a 120 psi I also use a 3/8 impact with a phillips socket to unscrew float bowl screws that have never been unscrewed before. It's way overkill but as long as you make sure the impact is running in the right direction it works the first time every time and I know you have stripped some float bowl screws. It's like karate chopping a brick,nothing you want to do half assed or you will wind up with a broken hand instead of a broken brick. Ha-waaaaaa!!!!