what my mechanic said...

[tonyk72]

I've been having problems with fuel leaks & smell with my Holley 4150. Its been driving me nuts for a while now...had new fuel lines installed, tried different base carb gaskets, new fuel filters...no luck.
So I brought it to a mechanic a fellow CAC'er told me about (thanks 82-Guy!)...and he found that my Holley will probably be need to rebuilt...it maintains a high fuel pressure which apparently contributes the gas seeping out and smelling when I park the car...
He also found the fuel filters in backwards and wrong fuel inlet fitting gaskets! Thanks to the 1st mechanic who worked on it! :blow

Anyways, the new mechanic, said he has worked on Holley's for 30 + years and that my problems (including hesitation on acceleration...he called it the Holley hesitation) are "the nature of the beast"...

My options were to either rebuild it or get an new carb...like an Edelbrock. He said it's no use bashing myself in the head trying to get the Holley fixed...

What do you guys think?

 

[dmrodco]

You'll be better off with the carter comp since they make the edlebrock anyway and carter parts are cheaper.

 

[Willis76]

Have you tired these guys?

http://www.recarbco.com

Just a thought for a little more information, etc. good luck -

 

[warren s]

I have had 4150s, 4165s and 3310s on some of my old Pontiac motors, from 350s to 455s.

Always liked them. Like anything else, they get old and rebuilding takes some time and experiance. They are very adjustable and usually reliable, but sometimes you just have to replace. I would go with a Holley if I had a carburated car these days.

 

[tonyk72]

I'm thinking I may go with a new carb...and rebuild the Holley myself in my spare time...bolt it back on one of these days and give it another go at it...

Edelbrock Performer 750 w/ electric choke is $199 @ Pep Boys
seems low to me, they would have to oreder it (5 days).
Another parts store has it for $265.


Is this a good replacement ?

 

[warren s]

From what i read the Ebelbrock carbs are pretty good. I never had one so i cant say for sure. Just remember to the the smallest one for your application, not the biggest for best performance.

 

[JohnZ]

Holleys are good carbs, and it's not "the nature of the beast" for them to have incurable hesitation or leaks. When they get old and too many guys have over-torqued the bowl screws trying to stop leaks caused by re-using cheap gaskets, it distorts the main body, and they can leak. A really professional Holley rebuilder will machine the main body surfaces dead flat, straighten the metering blocks in a jig, and use genuine Holley gaskets when it goes back together. Any hesitation can be tuned out with changes to the accelerator pump cam and/or the squirter nozzle. Holley has kits for both. A correctly-built Holley is a thing of beauty and a joy forever, but Bubba has been into too many of them.

 

[TWINRAY]

Rebuild the Holly yourself - it's basically a no brainer. Unless your a total incompetent, you can do it. It's easier than a Quadjet. Your problem is probably the power valves which are known to "blow out." I have a Holly in my '67 and it's bulletproof.

 

[warren s]

JohnZ

That is one great picture!!

 

[clar2001]

JohnZ
Great pic. Solid fuel lines very neet and Safe. No fire hazart there to many times people use soft lines from carb to fuel pump.I was told thats why there are so many corvette fires with the extreme temps under the hood..................

 

[tonyk72]

John, I'm glad you jumped in on this thread because I respect your opinion...I'd really like to get my carb the running the way it should & I'm not too crazy about accepting the fact that I just gotta deal with these Holley quirks. But what I find troubling is that 3 mechanics that I've talked to either don't wanna touch it, can't do the job right or tell me to just get a new carb...The last mechanic also said if I get it rebuilt I could expect the same problems to return if I let the car sit during winter storage...
He said that the Edelbrock would be a much better carb for a daily driver...

I guess what I need is a reputable Holley guy to rebuild my carb and do it right. I don't mind trying it myslef, but if 3 experienced mechanics don't wanna play with it...I'm not sure if I could get it right myself...especially with no experiece. I don't want to spend $80 on a carb rebuild kit only to find out my problem returns or becomes worse...What could I expect to pay a pro for a rebuild?

As for getting a new carb...I'd like to think it as a temp until I get the Holley fixed up...I'm also curious as to how the car will run with somethig else delivering the fuel...which leads me to my final question...how big a carb should I get? Edelbrock has 600 & 750 cfm carbs...Speed Demon has a 650...

 

[rainman]

I recently had a correct holley rebuilt and put on my 71 LT-1. It replaced an incorrect holley that was leaking pretty good. The car runs outstanding and I see no reason to have anything other than a holley.

 

[MoeJr]

Tony is your Holley the original to the car? If so then I would rebuild it for use later. In the interim a 750 Edelbrock with electric choke would be my choice for your car. Just my .02

 

[Redmanf1]

You can check the base with a straight edge and the vacuum secondary is also adjustable with different springs. There are many ways to adjust a Holley like changing the secondary metering blocks so you can do a four corner idle circuit, drill the front butterflies so it sets back in the idle circuit for big cam idle. There are many tricks for Holley's. Stay with the Holley just my .02

 

[Rodney Gold]

Where is it leaking?
If its from the fuel bowl nuts or fuel bowl to body/metering block interfaces , replace all the gaskets. You can get rebuild and gasket sets easily and there is a ton of stuff on the net explaining what to do
Check the aluminium transfer tube between the 2 sides of the carb for leaks (not sure if your carb has one)

There are generally 2 problems with fuel smells when the car is parked , Either the float levels are too high and fuel is leaking into the carb or percolation (the fuel percolates out the fuel bowls due to underhood heat and drips onto the secondaries and leaks out the shaft to the outside.)
The fuel pressure is really irrelevant , this would ONLY cause a leak in the fuel lines or where the fuel pipes join the float bowls as the float bowl valve should stop any excess entrering the carb
You might have a float that is leaking or is damaged but this would cause a lot of other problems when driving.

Fuel will not leak via the base plate/intake gasket , this would tend to be a vacuum leak and when parked , there is no fuel in this area generally.

You can EASILY check float levels yourself , let the car idle on a level ground and unscrew the brass plugs on the sides of the fuel bowls , the fuel should just drip out if you shake the car side to side.
To adjust this is easy - at the top of the fuel bowls there is a large screw with a nut under it , loosen off the screw and turn the nut clockwise to to REDUCE the fuel level in the bowls (if the fuel pours out) and ANTI Clockwise (Raising the float bowl fuel valve) to increase the level (if the fuel doesnt drip out when you shake the car)
Its a good idea to screw the whole valve right out and blow it clean and check the condition of the little rubber gasket etc.

For percolation , you need a heat shield or a shielding gasket tween the intake and the carb.
Also check the choke is fully open , not JUST the chocke butterfly but the whole mechanism.

Holley carbs are easy to work on and generally will work well right out the box if the motor is standard or slightly hotted up
and you havent put a monster carb on - generally owners want more carb and cam than motors do.
A Speadbore in the 600-650 range would be MORE than adequate for 350 motors revving to 6000 and making 300-350 hp and will give you the best compromise , loads of grunt due to the small primarys and lots of revs/power when the bigger secondaries come in , coupled with good fuel economy.

 

[tonyk72]

Moe, yes the Holley is original or at least the correct matching #'s carb...

Rodney, My mechanic pointed out that it's leaking from the rear fuel bowl top nut...he said when he went to remove the nut the fuel just started squiring everywhere...I witnessed the same thing a few days ago when one of my buddies at work was looking at the carb...The mechanic said when I park it, the excess fuel drips out of the carb...He also told me that the float seems to be stuck...
and the fuel bowls threads/nuts are fine and not stripped...
This is also causing my acceleration problems...
I already have a 1/2" heat blocking spacer...I tried this first when I started working on trying to solve my fuel smell problems...
But based on what you guys are saying now...the spacer is only a band-aid (which seemed to peel off really quick)...It didn't fix my problem...and it looks like I'll have to fix the floats/rebuild the carb...

Maybe I will try the rebuild myself? But I will still probably get that Edelbrock 750 for the time being...My projects usually tale 3x longer than I expect & I don't wanna have too much down time with my car...

 

[Rodney Gold]

That nut on the top has a gasket - it will ALWAYS leak out there if you loosen it off as the fuel is delivered there under pressure and the valve which is activated by the float either allows it into the float bowl or not , the nut screws the valve in or out the bowl , the higher the valve , the more fuel it lets into the bowl before the float shuts it. similar to a toilt cistern valve
Start by undoing the brass sight plug on the side of the carb and seeing where the fuel level is , the mechanic can NEVER make a leaky float diagnosis unless he removed the float bowl and inspected the float for a hole or for fuel in it.
It's most likely there is some crapolla in the valve due to the fuel filters being put in ass about face and the junk that they filtered is now pumped back. (Im assuming they werent new filters)
Disconnect your fuel line to the carb and insert it into a container to hold the excess fuel and release the pressure (keep car off) and then unscrew the screw at the top of the carb , turn the nut out (anti clockwise) which will turn the valve out (make note of how far the thread is sticking out of the hole in the top of the nut before unscrewing it) , just blow it out and make sure the rubber o-ring is not damaged or just buy another valve at the speed shop and replace it with that screwing it in more or less where it was before unscrewing it.
Im pretty sure your secondary's are flooding cos of dirt in the valve.
You really should remove the float bowl and see there is no gunk in it as well , all you need is a no 8 spanner and to loosen the nuts and unscrew them - this is slightly more difficult if there is a transfer tube tween both sides of the carb and you might not get it past the vaccum take off in the manifold - it's not THAT critical you do this step tho.
To clean the valve can be done in 5 mins or less.

 

[tonyk72]

Rodney, the fuel filters were brand new...would that make a difference?

 

[Thumper]

There are several reputable rebuilders that you can ship your Holley to for rebuilding. They know what they are doing and test the carb before they send it back to you. If you look in the back of most any hot rod magazine, you'll find the contact info for these people.

If something is warped, they will surface it back to flat. If you have a shaft bore that has become out of round causing vacuum leaks, they will machine the bore, press in brass bushings and reassemble to cure the vacuum leaks.

There are a couple of books that deal specifically with tuning Holley's. They are actually quite easy to dial in. These books will walk you through the process in great detail. You can find them at any Barnes & Noble, Waldenbooks, etc.

 

[tonyk72]

I found a Holley authorized repair shop in my area...The guy said it would be $95 for a rebuild with a 1 day turn around time. But they don't "wet test" the carb, they just put everything back to factory specs. This sounds good to me, although I'd like it if they test it too...A trained set of eyes might also point out something else I might not see...
I'm also assuming that after they finish it, all I gotta do is bolt it back on...I wouldn't have to fine tune anything...right?
I'm thinking I might drop it off Monday...be back in business by Tuesday night...I'll hold off on the new carb for now...

Are there any questions I should ask these guys? Are there different types of rebuilds? I don't want this guy to just shine this up and throw in a new fuel filter and say here ya go!