i have a 87 250 cyclone, it has been sitting for some time, i drained the transaxle fluid and replaced, i have new premixed gas in it, new plug, it has spark, the piston is not stuck (i removed the head and it slowly pulled the rope, and the piston was moving up and down) the top of the piston was very black, with carbon i suppose, i thought that i might need to rebuild the top end but after cleaning the piston head it looks fairly new, the only thing that i can think of is the carb, i took it off and chem tooled it, how do you know if the carb is working and if i have to rebuild the carb does anyone have any info, thanks