agree. more info needed
indicate what you've checked e.g for air leaks; condition of carb; crap in fuel
I had an almost similar problem with my B40 of not being able to get it to idle and having to hold the throttle open to keep it going and a bit of spitting when I throttle down. But it had idled ok not long before having just put it back together............turned out to be the air filter shaking itself off and affecting fuel fuel mix
I knew my fuel and carb should be clean, but was advised didn't need much. I didn't think I had air leaks at the engine manifold or too much wear in the carb
too much wear on the throttle s
I didn't think I should have air leaks