holley 4bbl tuning

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Jun 5, 2007 | 07:27 PM

*70F250*

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From: SO CAL

holley 4bbl tuning

hello all, well its a long story....i had a 289 with a 2bbl, i now have a 289 with a edelbrock performer intake and a holley 4bbl. all installed and timed correctly. but there is one problem, it doesnt want to run on no choke, only on 3/4 closed/choked. what is that about?? by the way, this is a rebuilt carb. soo, is there anyone out there who knows how to tune these things, and could give me some pointers??

oh and this carb is a standard 4160 model, the list # is 1850-2 and under that is 3428.

thanks guys

-brian

Jun 5, 2007 | 10:01 PM

kermmydog

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Joined: Oct 2003

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From: Western Central NV

If it won't idle without the choke being closed my guess there is a vacuum leak somewhere.

Jun 5, 2007 | 10:34 PM

*70F250*

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From: SO CAL

ok kermmydog, i checked all the hoses...looks good to me, everything is hooked up that WAS hooked up. i was just thinkin, this is probably a stupid question, but are there sopposed to be TWO fuel lines now, because of the 4bbl part?? my holley has 2 floats on either side of the body of the carb, and there is one hook-up on both sides for what iam starting to think is gas...i currently have one side hooked up to a fuel line, and the other is going to the valve cover cap...sorry its kinda hard to explain and probabaly hard for you guys to imagine. but general knowledge, do any holley 4bbls need two fuel lines??

Jun 5, 2007 | 11:39 PM

dmanlyr

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Joined: May 2005

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From: Puyallup, WA

Yes, some Holleys require a dual feed setup, one fuel line to each float bowl/chamber.

Some Holleys are set up with a built in fuel transfer tube, that goes between the two float bowls/chambers. These will have only one fuel line hookup.

Unfortuanlty, I don't have any pictures in front of me to send to you, but if you have a picture of your setup to post, I can tell you what system you have / need.

Maybe Kermmydog has a pic of the two types?

FYI - Holley carbs do not have any Valve cover / PVC hookups, the PVC was hooked up to a plate mounted between the carb and manifold (at least as of 10 years ago, maybe things have changed now??)

David

Jun 5, 2007 | 11:42 PM

LxMan1

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Joined: Dec 2001

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From: Louisville,Ky.

Did you adjust the mixture screws? They are either too far in or you have a vacuum leak, probably at the intake gaskets.

Jun 6, 2007 | 01:20 PM

*70F250*

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From: SO CAL

yes, i can upload and post pictures. it will be around 3:30 pm, iam at school and i dont have the pictures on this computer. i will definanly post some though. and lxman1, i have adjusted the idle screws (i think thats what they are...) to 3 turns out from seated. are there other screws??

hey thanks a lot guys for the help, iam REALLY appreciating it!

-brian

Jun 6, 2007 | 05:20 PM

*70F250*

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From: SO CAL

ok so this is looking from the top:

this is looking from the passenger side:

and this is looking from drivers side:

if anyone needs any more pictures let me know.

thanks
-brian

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Jun 6, 2007 | 07:35 PM

dmanlyr

Fleet Mechanic

Joined: May 2005

Posts: 1,575

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From: Puyallup, WA

You have a single inlet for the fuel, that tube that runs between the float chambers on the drivers side of the carb is what transfers the fuel.

I see the fitting that you hooked up to your valve cover, one thought comes to mind, do you have a PVC valve in the system? You do need one and it needs to be in the line that hooks up to that fitting (see below for other options), otherwise you wil have a rather large vacumme leak.

Third, most of those 1" spacer blocks under the carb have a rear fitting for hookng up the PVC valve, there is not a chance that yous has this fitting and it is open is there? That would also create a rather large vacumme leak.

To recap - So if you both of these fittings (the side of the carb, the rear of the spacer block) one will be used for the PVC system and the other should be blocked off. I personally would use the fitting on the spacer block for the PVC system.

I hope this helps, David