robmiester

Hello, my carb is leaking fuel (see pic.)

I did replace the gas tank, fuel filter, and electronic fuel pump. I'm thinking the problem may be with the fuel pump having too much pressure, but it was the same pressure as the last one. Also the car sat for a couple of months. (it's leaking at the circles)

Bluestripe67

I remember my old original Holley, it leaked at the transfer tube due to o-ring shrinkage. You may have that coupled with a little extra pressure. It may be new o-ring time. Don't hesitate on this, it has potential. Dennis

Allcoupedup

Have you seen it leaking from those points or are you assuming it came from the transfer tube? I ask because you'll see the same puddles if the bowls leak and leaky bowls due to warpage on the main body is common for holleys.

My last Holley rebuild kit came with some strange looking O rings - they were more like rubber sleeves and I had to cut them down significantly with a razor blade. No leaks though!

Brian

gonefishn

When they sit for a long time, as you mentioned, they are prone to leaking due to the gaskets drying out some.

My original one would leak then stopped leaking once exposed again to gas. Something to take care of though.

John

67vetteal

Holley makes a Modification Rebuild Kit so that the Ethanol in todays gas doesn't effect the Gaskets, Seals and "O" rings. Ethanol is tough on these older Carbs.! Al W.

SIXt7

Had the same problem on my Holley. Saw gas coming out of the transfer tube. Called Holley, they confirmed the o-ring problem. Got new ones and no problems. Good luck.

Coves4me

robmeister, If you're sure that's where the leaks are, try spinning the tube with your fingers. If you can, the o-rings are not sealing. If you can't, the tube may be too long and the float bowls have the tube in a bind. I have found tubes that were too long and had to shave 1/16-inch off one or both ends for the tube to seal. Also, it is better to have the tube short with 2 o-rings on each end. I also recommend that you install the new o-rings with petroleum jelly to keep from cutting the rubber. Good luck.

mpate

robmeister

Coves4me has provided excellent advice. I have been playing with the jetting on my carb and have had multiple opportunities to replace the orings.

Get a low profile aerosol plastic cap to catch the fuel, loosen one of lower rear bowl screws, insert the cap under the screw that you are removing. I typically will catch two full caps of fuel in draining my rear bowl. Following Coves4me recommendations, carefully reinsert the transfer tube into the front bowl and then apply the rear bowl. Do not use excessive pressure during reassembly or you will be replacing the orings again. Buy a couple of extra orings just in case they are cheap.

Mark

joec

Ok, so I'm no expert, but have done this several times... You stated that if it spin the xfer tube, it's not sealing. You also stated if you can't spin it, then the tube may be to long??? Ok, so I give up which is it.. Spin or no Spin... If I had my car home I'd check mine but I think it didn't spin one I tourqed down the bowl screws.. That being said even if the car sat for a few months it still shouldn't leak, mine never did... I would think the new fuel pump might have to much pressure, now that its new??? Let us know how you make out in either case..

/jc

chris ritchie

1. There's "O" rings that go on that tube in those 2 places you've circled. Those 2 "O" rings have a history of being troublesome. I believe Holley now offers an improved design.

2. Although the "O" rings leak a lot, the bowls leak even more. If the bowls were leaking, you'd get gas puddling in the same places. So, it's hard to tell what's leaking. If it's the bowls, tightening the 4 bolts will only make the problem worse. The reason they leak in the first place is because the parts are warped from being overtorqued. Check the straightness of the bowls, the body, and the metering block(s).

3. The late Dale Pearman had a sure fix for this problem. Go to a sporting goods store and buy a child's baseball batting tee. Put you Holley carb on the tee. Then take a baseball bat, and hit the carb as hard as you can. That will ruin the carb, and force you to replace it with an AFB.

BTW, get rid of that rubber hose feed line.

BarryK

For what it's worth, my Holley never used to leak but after I sent it out for a rebuild it leaked pretty bad. I was told by multiple people that the standard O rings on the fuel transfer tube and the fuel bowl screw gaskets that come in the standard rebuild kit are pretty poor.
The standard o rings are basic O rings and the fuel bowl screw gaskets are nothing really than cardboard.
I replaced the fuel transfer tube and O rings with a different kit available from Holley - the O rings are now more like sleeves rather than simply rings and the fuel transfer tube is slightly different I believe to handle the new O rings and the fuel bowl screw gaskets are nylon rather than cardboard.
since replacing both areas with the new parts the carb doesn't leak a single drop again.

Here is a pic showing the difference in the original 'standard" fuel transfer tube and O rings and than the replacement fuel transfer tube and new style O rings (sleeves).
The new replacement set is the set at the bottom:


This picture is showing the difference between the standard fuel bowl screw gaskets (cardboard) vs. the new replacement ones that are white.


Both the fuel transfer tube and the fuel bowl screw gaskets are pretty common leak areas so even if these are not currently the cause of your leak since you need to take the carb apart anyway to find and fix the problem you should consider replacing your parts with these to help avoid potential leaks in the future.

Last year when I did this the part numbers and costs from JEGS were:
Nylon fuel bowl gasket set. #0510108-98-10 $11.99
Fuel Transfer tube kit # 051026-114 $5.99

Oh, one last thing. when installing the O rings and fuel transfer tube put a small dab of vasoline or similar lubricant on the O rings to help them slide into the carb easier.

Tom E.

I had the same problem...

Rather than to continue throwing time and more money at (non-) fixes, (and worry about a fire from gas leaks), I finally just replaced the old @#$%!ING carbonator (sic) with the Holley Street Avenger System (and heat shield) from Summit Racing for a little more than $400.

Now, no problems; No more stalling, faster warm-ups, better gas mileage, quicker response----probably paid for itself.

tuxedo

I am glad this thread got started as I was just going to post about this happening to me. I have had the gas puddles in those areas before but then they just go away for the season. But so far this year the Holley isn't curing itself and the puddles seem bigger and quicker to come. I need to check as I don't know if it's the bowls or tubes. I clean up the area and then even after a short drive I will check and the puddles aren't there but if I come back the next morning there they are. I thought it might be due to percolation.

JohnZ

Those can also result from fuel dribbling off the ends of the throttle shafts if it percolates fuel out of the boosters AND the shaft holes in the baseplate are worn and need to be bushed.

robmiester

Yes I can spin the fuel transfer tube, yes it is coming from that point because I have seen it leak from that point. However there is some puddling on the other side which may be coming from the fuel bowls. I think the new fuel pump has knocked some things loose and I need new gaskets, and need to look at how high the pressure is.

I also need to switch out to metal fuel lines.......

67L36Driver

is a bowl shape heat shield with a bilge pump to return the leaked fuel to the gas tank.

rcameron

I know this is an old thread, so what Holley Street Avenger carb should I look at if I were to do a replace? I have a 327/350 '65 Vette.

Also, if anyone had pics/info on how to change out the o rings to the sleeved rubber gaskets for the fuel tube, would appreciate it!

Thanks!

USMC 0802

Depending on the specs of your 350, a 600 CFM unit should work. I replaced my motor with a 350 as well, but I went with a 670 CFM Street Avenger due to my cam, etc.

For me electric choke was a must, as well as vacuum secondaries.

I went with Redhorse lines with aluminum fittings on mine, so I cant help you on the o-rings.

Good luck!

Frankie the Fink

Many are going with the AED Holley-style replacement for non-original applications...

Jeff Garner

Pulled my 67's Holley again today due to severe leak from circle on top of rear bowl. Last time it was the transfer tube at rear bowl and circle on side of rear bowl.
I'm considering giving up on this original carb.
I see I can buy a direct replacement Holley 3810.
I'd like to keep everything OE, but looking ideas for replacement.