You could also pull the valve cover and check the cam chain and tensioner. But that's all ballpark from my end, I don't know too much to help ya other than the above rent a tool help lol. Try and see if you can get it to start on brake cleaner and idle for a couple seconds. It will burn clean and wont harm anything. Other chemicals have oily residue and will make it stumble and or not pop off. Good luck, Wish I could offer more help