Rough hi idle

[Purple440]

Bob I'm going through almost the same thing you are, except I'm idling rough below 180, and slightly smoother over 180.  Did the same hose checks and ran a propane torch along the manifold and carb spacer..nuttin 

I'll be trying a different carb tomorrow, the idea of an internal leak in the carb seems possible.  You should try the same if you can.   

G/L

- Doug

[Steve P.]

OK, went through the hoses again and plugged each one separately. Nothing changed. So I guess I'm back at carb. It amazes me how much you learn on a single string.

Bob

That is one of the best parts of this site. We all have run into something at one time or another and we are all here to share our minds..  Any time someone adds a bit of knowledge to a thread it is a great thing. It may not fix the posters problem, but many times other people have the same trouble at the time or down the road and they think back to things they have learned reading here..     

[Bob]

Bob I'm going through almost the same thing you are, except I'm idling rough below 180, and slightly smoother over 180.  Did the same hose checks and ran a propane torch along the manifold and carb spacer..nuttin 

I'll be trying a different carb tomorrow, the idea of an internal leak in the carb seems possible.  You should try the same if you can.   

G/L

- Doug

I'm on the search now for another carb. Seems everbody wants money for one.

[Purple440]

Bob I'm going through almost the same thing you are, except I'm idling rough below 180, and slightly smoother over 180.  Did the same hose checks and ran a propane torch along the manifold and carb spacer..nuttin 

I'll be trying a different carb tomorrow, the idea of an internal leak in the carb seems possible.  You should try the same if you can.   

G/L

- Doug

I'm on the search now for another carb. Seems everbody wants money for one.

Ha!  I noticed the same thing.  The only reason I have an extra is because I'm on my 4th carb 

You could try the "Will work for carb" sign 

[Bob]

Bob I'm going through almost the same thing you are, except I'm idling rough below 180, and slightly smoother over 180.  Did the same hose checks and ran a propane torch along the manifold and carb spacer..nuttin 

I'll be trying a different carb tomorrow, the idea of an internal leak in the carb seems possible.  You should try the same if you can.   

G/L

- Doug

I'm on the search now for another carb. Seems everbody wants money for one.

Ha!  I noticed the same thing.  The only reason I have an extra is because I'm on my 4th carb 

You could try the "Will work for carb" sign 

"Will work for Carb" 
Twilt would agree with that. He calls me cheap. I say frugal.

[Steve P.]

I tried the WILL WORK FOR CARB sign. It worked. I got a BG 850 Mighty Demon   

[Musicman]

You stated that this was strickly an issue with the idle once the engine is up to temperature. You checked for vacuum leaks and found nothing... but have you done the dummy check on your idle circuit yet? 

[Purple440]

... but have you done the dummy check on your idle circuit yet? 

[Bob]

Idle curcuit?

[Musicman]

Idle curcuit?

Idle Mixing Screws (Idle Air/Fuel Ratio Adjustments)... These screws are spring loaded and can end up out of adjustment over time, so you may be running entirely to lean or to rich at idle... either case will cause the engine to run rough at idle only. Or you may have a bunch of crap stuck in the valve seats. If the needle valves (idle mixing screws) do not respond to adjustment, then you probably have a bunch of crap in there. In which case, the idle screws must be removed, and the dirt blown out or otherwise physicaly removed. Since the idle circuit is not part of the normal fuel circuit, it has no effect on normal driving performance... IE: The engine will run great, except when at idle.
As I stated earlier, you should bring your engine up to temperature and follow standard procedures to reset your idle circuit.

[Bob]

Thanks Musicman