by lee » Sat Jun 03, 2017 4:08 pm
It does have the main jet in the bowl nut. I cleaned the carb, readjusted the idle mix screw, but it still hunts only unloaded at 3/4 to full throttle. I tried gradually giving it some choke to see if it would stop hunting, nope, it hunted until it choked down. Then I pulled the air filter off and put my little propane torch up to the carb inlet to give it a little propane to richen up the mix and see if that might stop it from hunting, nope. I backed it down to idle and waved the propane torch in front of the carb and it killed it. So I'm not sure if drilling the main will help this poor old Briggs or not. Today I pressure washed with it for almost an hour. Full throttle, 3600 rpm on the tach, fully loaded it never misses a beat. Let off on the wand trigger, goes into bypass, starts hunting. The fact that it runs great at idle and at full load eliminates a lot of things that could be wrong. Is it possible that it's hunting due to being too rich when it's unloaded at full throttle? I've never seen that before on a fixed jet carb like this. I have seen it on engines with an adjustable main jet if you back the jet out too far you can make it hunt due to being too rich. The carb isn't flooding and it idles fine. I've seen a leaking needle valve cause the carb to flood and it would run full throttle but would smoke and choke down and die at idle.