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Guys, hoping for some guidance on my Holley 1940 manual choke carb. It's on my 240cid on my 1965 F100 (manual transmission). I've bottomed out the slow idle adjustment screw - circled in red in the example pic below - and still can't get the idle below 900 RPM. I have the idle mixture screw nearly bottomed out but that has a minimal effect on the RPM. I don't think changing the jet would affect the idle but at this point I'm open to suggestions. My suspicion is there's something obvious that I'm missing. If I completely remove the slow idle adjustment screw the RPM is still high so I'm very confused. Is there some bending of a tang on the throttle linkage/cam that I need to do? Thanks for any ideas.
Dan, you are correct. Something is wrong on mine. I have the idle screw backed all the way out and it is still idling too high. When I compare a picture I took of mine the cam is installed differently. The throttle cable connection is below the pivot point on the stock picture but above the pivot point on my carb. I assumed when I bought this one that it was assembled correctly but maybe something was flipped around.
I think you are missing the return spring for the gas pedal cable and the natural running engine vacuum is raising your idle because there is no spring. The cable is sensitive to sticking and the clamping of the throttle has to be just so----so before you start it be carful the throttle does not open completely.
Thanks guys, I appreciate the advice and ideas to try. I’m traveling for work until Sunday late afternoon so I won’t be able to troubleshoot until next Monday. I’ll let you guys know how it turns out which is code for I’ll be asking more questions if it doesn’t work. Thanks again!
04-29-2022, 03:33 PM
