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Bog or Stumble off idle

3711 Views 7 Replies 5 Participants Last post by  tjstarduster
I had my Holley 780 rebuilt a few months ago and I've noticed the car has developed somewhat of a bog, or stumble off idle as I'm letting out the clutch. After a second or two, the engine catches and the revs go up.

Any idea what might be causing this? Carb idle mixture screws or accelerator pump?
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Look at the accelerator pump first. Take off the air cleaner and using a flash light watch the squirter while you open the throttle. You should see a stream of fuel immediately into both venturies. Adjust the pump arm if you aren't getting that shot just as the throttle opens. In my case I had to increase the jet size to fix a bog but if the carb was rebuilt with all the same settings it's probably just an adjustment somewhere. Check to make sure all the nuts (carb to manifold) are still tight since you just installed it recently.
the jets aren't generally involved in off idle stumbles. or are you talking those off-idle stumbles the involve WOT?
Tom is correct (as usual :)). My bog showed up more during light throttle opening at low speed cruise. Using a huge squirter helped the problem but jumping 6 jet sizes was the fix.
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