I'm a Briggs nut, but if the parts to rebuild correctly cost more than $100, I would go for the HF 6.5hp motor at about that price and brand new. Sounds like your cylinder won't last long without being way down on power and or smoking heavily. Also Generator motors often have a special crankshaft that has no provision for a clutch (like a keyway) and don't want to separate from the armature easily. Although, the footprint, base and mounting measurements and crank position will be the same as the HF motors as well as Hondas, etc. So it would make a great mock up motor for a bike project and you could run it as long as it lasted before swapping out with a good one. You can overcome the crank problem if it's a common diameter by drilling a hole in the side of if for the clutch set screw, or filing a flat for the same. Free engines are always a treat. Good luck.