RE: Pumped OS FS-91 surges at full throttle
Thanks, Bax. I am not using muffler pressure and the tank installation works well for my other pumped 91 (this one is down awaiting a new bearing - that's why I'm running the second one). Since the problem engine does run well when it isn't surging, I'm thinking that the mechanical potions of the engine are ok ( I did check the valves and the adjustment is ok). Since I changed out the pump with no effect, that leaves the carburetor, regulator, or needle vlave. I guess the next step is to swap out the carb body and regulator with the other engine and see if that isolates the problem. Before I do that, is there a good way to flush the regulator and carb body? Perhaps there is some trash in there.
Thanks for your advice.