choked carb

[ScottyG]

This past week, many of you answered questions for me about timing and carburetor problems. Through a timing adjustment, I managed to get plenty of power out of ol' Henry with the one exception that at mid to high speed, I was now getting an exhaust noise like "foop, foop", kind of a mini-backfire. I was instructed to check for leaks and I think it was either GW, Jim or BigDog who told me it might be valves.

I did a little more troubleshooting tonight. I took the carb apart (about the 7th time in two weeks) straightened the top, checked the float height (1-13/32") and put on a new gasket. The carb is good and tight with the exception that the idle tube broke off with the base of it still in the carb's top. I was told that since that little piece is still in there, this should not affect operation so I left the tube out.

Anyway, when I refired, the foop foop noise proved to be even worse than before. I'm also getting a slight governor surge. I think I've isolated the problem though to a vacuum leak. If I choke about 1/2 way, the engine runs as smooth as glass. Take the choke off and it's nothing but chop. There's a new gasket on the carb and one on the intake manifold. The only two that I haven't replaced are the manifold to block and the valve cover. I have plenty of fuel running into the carb and to my knowledge, all of my jets are clean. I also tried removing the air cleaner hose to see if there was blockage. No change here. Any suggestions? I'm about at my wit's end!

[TrainsNTractors]

you could try to spray some carb cleaner around the intake and see if things smooth out. If so you might have found your air leak.

[ScottyG]

Carb cleaner huh? Thanks, I'll try this and report back.

[beaconlight]

Scotty every time I have had mine running like that it was dirt or rust in the carb. Took it apart blew it out and all was well. I don't have any idea about how the broken idle tube would affect it.

Bill

[ScottyG]

Hi beacon,

Got it fixed and you guessed it; varnish in the main jet. Thanks for your help.