I did an engine swap for a friend and have the bad Walbro fuel injection engine on the bench. If you turn it by hand about every 4th turn it catches and wont keep turning. No visible engine damage I have the case split. If I pull the cam it spins easy no catching. Cam looks perfect. Head and push rods are also removed. Anybody ever see anything like this? Cant figure it out. I would like to repair the engine and sell it but I'm lost!!!