Ok so here is my dumb question of the day, I will explain first. My camaro has a 350 .30 over. It had an Edelbrock Quadrajet 750cfm (that is what the guy had on it it before i bought it) on it but was giving way to much gas. I moved over to a Holley double pumper 650cfm thinking that might fix the problem of it drowning it with gas. To no avail, the holley is freshly rebuilt, it leaks gas with no matter how many adjustments, Took it to a mechanic and they said it needs to be rebuilt even tho it had just been rebuilt. Ok now for the dumb question that I'm thinking is the answer that I have read, It doesnt have a fuel pressure regulator, it goes from the gas tank to a mechanical fuel pump, to a filter straight to the holley. Could it be that simple of a fix for it? and if so what would y'all suggest for one that isnt overly expensive? 2 different mechanics have looked at it never said anything about it needing one, The car didnt have one on it when i bought it.

 

First question is where is the gas leaking from? This is very important as if it comes from the bowl vents you have float setting issues or too much fuel pressure.

Next question is have you measured the fuel pressure at the carb? That should be the first thing you do before anything else with the fuel system.

Most mechanical fuel pumps with supply 6-8psi to the carb. Most carb manufactures recommend no more than 6 psi.

There are many more issues that need to be address depending on what and how the carb is leaking. Just because the 650 was rebuilt doesn't mean the floats were set or they fully removed the throttle shafts and replaced the end seals.

One other thing is what kind of mechanical fuel pump is on the motor? A return style or non-return style. The fuel pressure reading and where the fuel is leaking from is also helpful here to determine if there is a fuel pump issue.

Usually you can get by without a pressure regulator when running a mechanical fuel pump and depending on how the carb is leaking they might be right with questioning the quality of the rebuild since they know nothing about the condition of the carb to begin with.

 

There is several places it is leaking from on the carb, and it gets worse or better as im adjusting the floats but never fully stops. I will look tonight when I get home from work and tell you exactly where its from.

The mechanical fuel pump i picked up from autozone, yes it does have a return, but I dont remember the brand right off hand.

No I haven't measured the fuel pressure. I will have to pick up a gauge when i get paid and check it.

 

The pumps brand really doesn't matter right now. Those pumps are internally regulated and the excess fuel that is not going to the carb is returned to the tank. If for some crazy reason the return line is blocked it can cause pressure problems with the feed to the carb. Not saying that is the problem but that is why you need to check the fuel pressure.

While you are adjusting the floats gas will leak out of the float adjusting nut area which that is normal. There is a seal under the nut and a seal between the nut and the locking screw. If it continues to leak there after you tighten the locking screw then you have a bad gasket and I would replace both since you are there.

Go to http://www.holley.com/data/TechServi...ech%20Info.pdf This is a good article for how to tune your Holley carburetor.

More tech articles here http://www.holley.com/TechService/Library.asp

Post up what you find out