I am new to working on this type of engine.

I have a Murray snowblower that I bought in 1995. It has an 8HP Tecumseh engine on it.

The problem is: It won't idle, and even at full throttle and no load it constantly revs up then idles down, revs up then idles down, revs up then idles down over and over. When I start throwing snow with it it smoothes out. If I try to idle it to go do something else it will stall. Do any of you know what i have to do to remedy this. I already changed the spark plug. I did gap the new plug at .027 like the one I took out.

gap should be .30 but doesn't sound like its causing it. carb probablly either got a little water, or trash in it, of course some do it till they warm up and the carb gets warmed up.

idle circuit is plugged up the center of carb body there is a small hole that gets plugged needs cleaned

Thanks. I will try and clean the idle circuit this weekend.