Idle not returning to normal

[49 Dodge Dude]

Well, I got my rebuild kit in and rebuilt my Stromberg carb. Put it back on and fired her up. No leaks, and idle is nice and smooth. Unfortunately, when I press on the accelerator and release, the rpm's stay high and don't return to normal idle speed. I've checked the linkage - it's not kinked anywhere and it returns like it's supposed to.

Any ideas what may be causing this?

[greg g]

Is the idle adjust ment screw misadjusted? did you alter the return spring placement, did you lengthen the adjustment on the throttle linkage? Is anything obstructing the free and full movement of the acc pedal? Is your idle mixture adjustment screw properly adjusted?

Edited April 7, 2012 by greg g

[JBNeal]

it kinda sounds like the plunger inside the carb is not returning to the idle position. The leather seal needs to be soft, so let it soak in gasoline for a day or two so the leather will be saturated & lubricated. The plunger's movement is impossible to check with the air horn in place, so you'll have to pull the air horn & approximate where it sits to verify plunger movement. I had a similar problem with a Carter B&B and found that the plunger linkage wasn't set properly using this approach.

[greg g]

can't see what the accelerator pum has to do with a high idle, but it don;t cost nothing to look. Also check to see if your high idle cam is returning to the correct psoition when the choke is fulley opened. Is you car equiped with a fluid drive anti stall dash pot? is it in its correct position?

[Dodgeb4ya]

Check the throttle shaft lever for being wobbly and loose to the throttle shaft-common issue on the 1BBL strombergs and will cause your issue because the throttle shaft doesn't accurately follow the throttle linkage and lever. Very common on the M-6 Stromberg carb. The side lever was originally swedged to the throttle shaft and people try to repair this issue by soldering and other means that don't work. Hopefully you have a idle adjustment or linkage hang up.

Bob

[49 Dodge Dude]

Thanks for the suggestions. I took the carb back off and found one of the plungers was sticking, so I loosened it up and put it back on. It now runs great and works the way it's supposed to. I'm posting a before/after pic. Someone in the past had spray painted the carb silver, and over time the paint crinkled and flaked off. I got it nice and cleaned up and I think it looks a lot better!

Thanks for all the help!!