I have a 34cc Briggs & Stratton Fource 4 cylcle motor converted for aircraft. I made a spacer for the carb and cut the spring tension back on the throttle. It will run at idle or with the choke almost closed. I thought it may be sucking air. Checked the gaskets and they are not leaking. I think when I trimmed the spring for less tension that without the tension it leaks in air around the barrel. Any thoughts on changing the carb or fixing this problem.

I don't want that spring tension on the servo all the time so would like to find a more RC friendly carb with less tension and easy movement.

Thanks,
Eric