holley high idle

[ellisteam1]

Went to adjust my carb and 2 idles screws out still rev 1200...rpm---butterflies are hiding the transition slot--idle mixture screw goes from 3/4 to 1 1/2 to get 12 in vacuum and 1200 rpm---also litle fuel is running in the vacuum gauge tube like pulsed shot... any idea---350 chevy--650 holley--single plane--need help to undersatnd,,,,

[travis]

I’d be looking for a vacuum leak...

Where are you connecting your vacuum gauge? If the idle speed screw is backed out to where it isn’t making contact, then it’s got to be getting air from somewhere else...possibly the secondaries are open too far (or have holes drilled in the secondary throttle blades)

[ellisteam1]

connected to spacer under the carb....secondary are closed and hide tranfer slot too.......

[cv67]

You are seeing fuel in the line of your vaccum gauge is that correct?

[ellisteam1]

yes....fuel in the vacuum gauge tube

[dannobee]

If it's idling at 1200 with the throttles closed, it's gotta be getting the air from somewhere. Vacuum leak at the base gasket, under the intake manifold, brake booster hose. It's leaking air/vacuum from somewhere. If it still has a choke, is the fast idle cam still on the throttle shaft?

[ellisteam1]

.....no choke ....no brake booster....race engine....gaskets are ok........Gonna try another carb tonight and let you know....

[BillK]

What intake ?

[ellisteam1]

brodix hv1000 (single plane)intake......yesterday i put another carb(pink holley 650dp)---12 in vac---1200 rpm---idle screw way out both shaft...but no fuel going to the vacuum gauge tube like first carb....Maybe should try to block holes in the butterfly and see...all transfer slot are hidden.....

[rp930]

Where is the timing during all of this?

[ellisteam1]

...timing 35.......fixed timing........

[shoedoos]

choke the carb with your hands, if it still idles, you have an air leak somewhere....and yes, get rid of the holes in the butterflies unless you have some monster cam. Might also be time to look at putting weights back in the distributor and ramping the timing if all the other ideas don't work to bring your idle down....

[rp930]

choke the carb with your hands, if it still idles, you have an air leak somewhere....and yes, get rid of the holes in the butterflies unless you have some monster cam. Might also be time to look at putting weights back in the distributor and ramping the timing if all the other ideas don't work to bring your idle down....

This.

[miniv8]

Did you do a camshaft change?

[ellisteam1]

no cam change......i did block the 4 holes in butterflies.....idle screws are now back on the shafts....900-1100 rpm ...vacuum is 10-11 idle but i can run with 2 left idle screws all in and the rh side at 1 1/2 turn frt and 1 3/4 rear.........now .....idle air bleed to get my lh screws out..????Thanks guys for helping......