I recently bought a used 52" scag hydro advantage mower. When I release the parking brake it cuts the engine off. I replaced the parking brake switch, but I'm having the same problem. I disconnected where u plug into the parking brake switch, and it works. I'm also replacing the blades with scag Marbain blades. How many spacers should I put between the blade and deck for best cut? Ive also heard if u adjust the pitch u will get a better cut, not sure how to do that. Any thoughts would be appreciated.