So here is what I have, a 91 Trail Boss 4X4 250. I rebuilt the motor upper and lower ends. replaced all seals bearings and gaskets. Got it all together and it started right up so I got one issue fixed. I noticed where the U-shaped exhaust pipe meets the tail pipe/muffler there is something spritzing out of the pipe junction that smells like fuel. As well the U-shaped pipe is extremely moist on the inside which leads me to believe that I am getting too much fuel possibly, or my muffler may be clogged and producing too much back pressure. Then I thought well darn I forgot to clean the carb, So I cleaned it and now it will not start at all. I am not sure if I have the Air pilot screw set right. Or the Throttle Set Screw set right. I am getting awesome spark, but am unsure with boring it out .040 oversize using a 73mm Wiseco piston, does my gap on my spark plug need to increase as well? When I bored out my 74 CJ5 V-8 I had to incres the gap from .035 to .043. I have not figured out the right combination yet to get this machine running great. Any pointers would be appreciated more than writing can show.