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Holley 750DP won't idle down

9K views 24 replies 7 participants last post by  baloo28 
#1 ·
Ok...strange one here. Yesterday I ran my car, 427 BBC, 4 sp tranny and it was great! Idled nice, timing real close and came home from getting my tires installed.

Today I fire it up and it won't idle down. No choke hooked up. Vac advance hooked to bottom of carb at front cuz there isn't a port on the metering block.

I turned out the idle screw and now it's about to come out. The cable isn't hanging up, the plates are closed, and I don't see any gas leaking in the bores.

I'm really lost.....
 
#5 ·
Sadly no....I bought it from a gent here. He rebuilt it and it was working perfectly for the 3 weeks I've had the car running, last night it just started acting up..I"m going to pull the vacuum hoses and caps first, make sure the throttle plates aren't stuck, then go from there. Got a friend who is gonna look at it tomorrow and if we can't figure it out, I'm gonna buy an Edelbrock.
 
#6 ·
OMG.

a bad solution to a minor problem. did you check to see if the sec throttles were hung open? check to see if it's not a carb problem at all, maybe a vacuum leak? linkage hung up?

OTOH, buy an Edelbrock and send me that cruddy Holley. :)
 
#14 ·
Remember to start a new thread when you have lean condition problems.
 
#15 ·
Obviously, you need the service offered by my new company, "Tom's Free Junk Holley Disposal Service." All you have to pay is the cheap one-way shipping to me and I'll see that the junker is properly disposed of. NO Environmental fees charged at all. Special, for you, today only, etc, etc, etc. ;)
 
#19 ·
you weren't serious??? I got a box of old parts Holly's on the way to you...:(
 
#20 ·
Yes! Yes! I was serious!! As a heart attack. Well, let's don't go there....

SO, what address did you send it to? 123 Main St?
 
#22 ·
I'm working on a new marketing idea where they'll pay me to take those junk Holleys off their hands. Right after that I'm getting a job with the Fedal Gummint.
 
#25 ·
Ok, here are the numbers off of the carb

4779-2 Holley 4150
Primary jet 70
Secondary jet 80
Front power valve 6.5
Front discharge nozzle .028
Rear discharge nozzle .031

It was rebuilt within the last 3 months, but one thing that bugs me is the front metering block has no provision for my vac advance connection, so I had to go with the full vacuum connection at the bottom.

If I were to rebuild this carb, should I get a new metering valve that has this connection and as long as I'm at it, the secondary metering valve does not have any adjusments for a/f. Should I get that one too?

Thanks!!!
 
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