You are going to have to give us more info before we can tell you how to proceed. First, give us the full engine numbers, model, type and code. That way we will see your exact engine. Second, you say engine won’t start. Does that mean, won’t turn over or turns over, spins, but doesn’t start? Third, have you checked for spark? Fourth, are you sure the cylinder is getting fuel? Fifth, is the carb getting fuel? Sixth, how fresh is the fuel? Seventh, did this problem occur suddenly, or has gotten worse over time? Eighth, what have you done so far to solve the problem on your own? I know that I’m asking a lot, but you must remember that we are not standing next to you with a drink in hand, looking at the unit. You must paint us a better picture of what is happening, or we will just be throwing guesses in your direction, trying to see what will stick. DIY guys do that, the techs want good information before throwing money at the problem.