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Discussion Starter · #1 ·
Engine:289 SBF
Carburetor: Holley 4160 600cfm
Fuel Pressure: 4psi regulated

Recently I sent my carburetor to be rebuilt. Upon installation and initial test of the rebuilt carburetor I encountered extremely rough running condition at idle and through the rpm band. I adjusted the floats per Holley instructions. On inspection, I observed fuel dripping down from the venturi boosters on the primary side.

I pulled the carburetor and removed both bowls to check the needle and seat for proper operation. Both open and close as they should. I also took the time to dry set the floats to the positions specified by Holley. I checked the power valve, the diaphragm is intact.

I tested the carburetor again with the same result.

I drained the fuel from the bowls and set the floats even lower. So low there was zero dripping from the sight plug. The car is still dumping fuel into the engine with the same result.

I have also tested this on a 351w with the same rough condition.

I would like to know what I am missing here. The standard procedure for flooding is checking floats, needle and seat, and fuel pressure. Is it possible that some parts were left out during rebuild or incorrect parts were used? What else would cause this type of operation?
 

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Check the fuel pressure while you are driving. Iknow you have a regulator on it.. but check it anyway.

I had some crazy issues with my holley idling like crap at random... and I found my 'o.e spec' parts store fuel pump was making as much as 10psi when I slowed to an idle...

to that end.. your regulator might not be doing it's job..
 

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Discussion Starter · #3 ·
Currently it is undrivable. It's not just at idle, it's rough through the rpm's. The fuel pressure gauge reads 4psi at regulator, I had initially tried turning it down from 7 with no effect.
 

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you may want to make sure your power-valve isn't damaged..

*oh* I just noticed you have the 600cfm holley. .that's a single-feed isn't it? it's got the fuel transfer tube on the side..

I had a holley like that once.. best thing i ever did was chuck in the nearest lake and a got a 650cfm dual-feed (looks like a double pumper, but it's still a vac secondary) for some reason, no matter what I did with that 600 I couldn't make it run right.
 

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Discussion Starter · #5 ·
It looks like buying a new one is the only way i'm going to be able to resolve this. I can't get any good information on how to fix this old one.
 

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Discussion Starter · #7 ·
I will be sure to inspect the squirter area the next time I have the carb on the car with the new needle and seat valves. Thanks for the link.
 

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Before you go buying a new carburetorI had the same problem like you did and fuel pressure was not the problem as I was only 6 psi and those side hung float bowls really suck at dealing with fuel pressure and having proper level on them.

I had the non adjustable ones and they were adjusted by holley and I never touched them and I had problems with the fuel dripping out the boosters which lead to either too much fuel pressure or to high of a float level. So took apart and the floats were right were holley put them so I bent the tangs to readjust them a little lower but still did not help.

I have a fuel pressure gauge and it was fine so I then ditched the non adjustable bowls for a old set of side hung bowls I had from a older carb and they did the same thing and had to have the floats way low in order to get proper fuel level but that was not the correct for them to operate.

Got rid of the fuel dribbling problem from level being to high but the floats were always too low and if getting on it long enough would cause too low of fuel level. Even tried fuel regulator once and it made no difference.

I finally said the heck with it and ditched the side hung bowls and bought a set of center hung fuel bowls from allcarbs.com pretty cheap and now I have the correct float levels and have eliminated the problems the side hung float style caused me.

Just reread you post and saw you have the adjustable bowls and I would suggest if you can get a set of center hung bowls and the hardware for it and you should be good to go. At least that worked for me.
 

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The other thing to check is that the correct gasket was used between the metering block and the body. Depending on the model there is a difference and it will have the same symptoms you describe. A lot of the rebuild kits contain both gaskets so it's very possible to get the wrong one installed.
 

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Is this fuel dripping at idle, or after the engine is shut off? If it's dripping after the engine is off, then you've probably got a bad float needle, or crud in the needle or seat. If you paid someone to rebuild this carb I'd contact them and tell them of your problem. It should be a warranty repair, so send it back to them.
 
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