Also make sure the rewind cover is not bent. That will make them pull hard if it has the old style rewind. If it hit real hard it could have broken the compression release weight off of the cam or maybe it stuck in the cam gear. A gasket set for the B&S engine is cheap. I would remove the rewind cover and flywheel. If you do not find anything wrong with it then take the crankcase apart. The compression release is a mechanical one and is easy to inspect visually.
Crazy thought. I wonder if the scopes, that you can get to look into a wall or such, would fit down the oil fill port??? Never tried it on a small engine. I have use mine on tractors. Mainly looking into the rear ends and such. Just a thought.
Truthfully I kind of think B&S are a throw away engine anymore. The quality is just not in the league with a good Honda or Kawasaki.