I just put in a new nickasil piston ring, and new gaskets. Then cleaned all the parts. Now that i have it back together it took forever to get it started. When I get it started it will start if i full throttle it , and it will not idle. We tried moving up 3 sizes to a 76 jet, but it won't idle. Turn the idle screw in all the way, it just won't idle. I put in a new spark plug. we checked the fuel. I'm at a loss. could it be a weak spark? or could the coil be bad? any suggestions?