BeansWorld

Hi team,

Attempted to start the car and it was running ROUGH with very low idle (400-500) before stalling. I'm smelling fuel, so I remove the air cleaner and see a small amount of fuel pool on the rear of the intake manifold. I put my fingers under the carb and it's very wet - definitely fuel. It's not coming from the fuel lines but seems to be coming from a plate in the bottom rear of the carb? I know nothing about carbs but can take a picture:



Could it be as simple as tightening the bolts that connect the small plate to the bottom of the carb? The picture seems to show a black gasket that could possibly require replacement? I assume I need to remove the carb to accomplish this task. Is there anything I need to be aware of before proceeding?

Thank you all for the assistance, I can't wait to get back on the road!

Regards,

Eugene

Jbster

How old is your carb? Ethanol is hard on carb gaskets. If it's old, I would rebuild it. Once one gasket fails, others may follow. Check the condition of your rubber fuel lines at the fuel pump and tank also.

BeansWorld

Jbster,

The car was a late 90's frame-off restoration. Probably driven 6k since complete. That said, this carb must be 11 years old at a minimum. It was running great (always has) until this fuel leak. I had noticed some fuel at the rear base of the carb earlier this year, but it was a small amount, enough to dampen your finger. This is now how the front base of the carb feels, so I suspect this will leak as well.

Here's a pic from a Super Chevy magazine article on Holley rebuilds. This is where I'm thinking the leak is at:





Is a carb rebuild a difficult task? I've never rebuilt one but if the steps are clear and I don't need specialized tools, I'm thinking I'm willing to do this myself. My biggest concern is tuning after completion (if necessary).

Thanks,

Eugene

540 vette

Go to Amazon and you will find all the Holley rebuild and tuning books you could ever need. Also you could probably find help on the web and of course this forum has some very knowledgeable carb guys.

Shark Racer

Holleys are VERY easy to rebuild.

Mpls Funk

I will be watching this thread very closely. I have the same problem. It was suggested to me to replace the "pumps" (I believe that's what they are called...they are the things you show in the picture you posted). I did that, and they admittedly looked very dry and crappy...that replacement was VERY easy. Unfortunately that didn't solve my problem. It is not coming from my fuel lines either...I can't find it, but mine is leaking quite a bit...very frustrating.

mrvette

Poor guy, MY name is Eugene also......I go by GENE, always misspelled by everyone as JEAN.....grrrrrr.....


but as to the carb, age 70 here, working on cars for pushing 60 years now, never saw a Holley carb that did not leak fuel it's part of the design, and you can rebuild that POS from now till HELL freezes over and it will leak, go to most any cruise night, look close at the cars with Holley carbs on them, you see evidence of fuel leaks/stains all over them, even though the rest of the car is brand new......

As a result I have never owned/allowed a Holley carb on any of my cars.....


but of course I found a FI hose the other day dripping fuel over the headers.....I about freaked out......

terrys6t8roadster

Let us not forget that most of the fuel that we buy has ethanol or some form of alcohol, which rots out the black accelerator pumps on our Holley carbs. I've been running the green version, which is designed for alcohol for years with no problem. T

BeansWorld

Mrvette, being "Eugene" in the 80's was tough as a kid, but now I embrace nerd! Nerd skills allow us to rebuild carbs ourselves!

I ordered the quick kit from Holey 510-37-1546. Stay tuned, I should be able to get to this by next Wednesday. I'll post some pics and results by next Friday (hopefully).

Thanks to all with your responses, you've all been very helpful.

CaseyJones

I knew a guy named Eugene growing up. Trust me, no one EVER made fun of his name. He could be a best friend or a worst enemy and was just that kind of a guy. He is the one person you always wanted on your side in case of trouble. I still consider him a good friend even though I haven't seen him in years. He was a Mopar guy and owned some really nice cars over the years.

As far as Holley carbs go, I have had several over the years. I always carried a small screwdriver with me because every time I cranked up my car I would pop the hood, adjust the choke, the idle or the mixture or all three, shut the hood, and drive. They NEVER ran great two trips in a row and always seemed to leak from somewhere. Finally tossed all of them and I now run whatever the factory put there with the changes necessary to fit my build. Carters on Mopars and Q-Jets on Chevy's. No more fiddling every time I drive something.

I don't want to open a can of worms here, just my experiences.

BeansWorld

Mrvette,

I definitely forgot to mention all the stains on my intake manifold - but most are not fuel-related A few antifreeze leaks prior to the Vintage Air install. Ugghh. How the intake manifold gets back to show-worthy I'll never know. Suggestions??

The carb is now off, it took all of 5 minutes. Lifted right off with no issues. My biggest concern during the (minor) rebuild is keeping the tune in order; the car was tuned on a dyno and ran perfectly prior to the fuel leak. I plan on replacing the accelerator pump gaskets, metering block and float bowl gaskets. I don't plan on replacing the gasket to the throttle body unless convinced otherwise here on the forum. It's a ton more work and I'm nervous about adjusting the carb tune, or really any more work than absolutely necessary ,this being my first carb issue EVER.

Ultimately, I'd like to get this carb running as previous. I have the original Rochester in storage but with an engine build I suspect this will require a tune I'm not capable of. I'd consider an EFI setup (its already resto-mod status) but after the Vintage Air install and other hobbies it's a price I'm not ready to absorb.

Anyone been in this situation?

Thanks,

Eugene

BeansWorld

Turns out the carb rebuild was a simple process. Clean everything with carb cleaner, use compressed air to blow through air passages etc. Take lots of pictures, it definitely helped me.

Just one last issue - I did not pull out the fuel inlet fittings since the vinyl gaskets were not included in my kit. And of course one is leaking. Everything else is dry and the carb is running great. That said, two questions:

What's the torque setting when I reinstall the fuel inlet fitting? The PO used white pipe tape around the fitting, should I do the same?

Duane4238

Check your rebuild kit for a similar size gasket made of another material besides the white vinyl I see in your first photo. It will probably be a dark red fiber gasket, instead. Do not, I repeat Do Not use teflon tape on the fuel line threads. That fitting has a tapered(flared) seat that is self sealing as you tighten the fitting. If it leaks, it's not at the threads but at the seat of the flare. If you use any kind of tape on the threads, you take the chance of getting a piece of it inside your carb. That could hold open the needle valve and cause flooding, or block a fuel passage and cause all kinds of problems. As far as the torque specs for tightening, I can't help you out. I've never measured how tight it should be. Just tightened carefully until it doesn't leak. Good luck.
Duane

BeansWorld

Thank Duane, I thought the same thing; the thread pipe material could easily get into the carb... I had installed this way but pulled the fuel inlet valve before running.

One of the inlet valves was not brass / was a sh!tty fit, so I ordered a new one with new vinyl gaskets from Jegs. This one was the source of my leak. My original kit included metal washers that were the same diameter but extremely thin. I should have everything back together in a few days.

If anyone has a torque recommendation....

Mpls Funk

I think you mentioned that you had never taken a carb apart before, correct? How long did this take you to do? I have a feeling I need to do the same thing and am a little intimidated. You don't have the car running yet, do you? I'm also interested/intimidated by getting it running/tuned after putting it back together, etc. Interested in your comments...

BeansWorld

Mpls Funk,

It was an easy process, though the carb was tuned properly prior to the fuel leak. I disassembled, cleaned with carb cleaner and installed the new power valves, metering block gaskets, throttle body gasket and accelerator pump gaskets (with new umbrella grommets). I did not disassemble the needle and seat and made no other adjustments.

It started and ran excellent at idle, but a small amount of fuel leaked from the secondary fuel inlet fitting. This gasket was not previously changed (and the nylon gaskets were not included in the kit I purchased). I have new gaskets on order and should be able to complete the process this weekend. My only question is proper torque setting on the fuel inlet fitting. I'll keep digging.

BeansWorld

So I've replaced both brass fuel inlet fittings and nylon gaskets. The secondary fuel inlet is still leaking just a bit, but it's leaking where the fuel line connects to the fitting, not at the nylon gasket to the float bowl. Very frustrating. I've pulled the fuel lines, cleaned threads and made sure to insert flush and tighten evenly. There doesn't seem to be any imperfections on the fuel line.

Any ideas how I resolve this final step? I'd love to go for a drive...

Thanks,

Eugene

F4Gary

It's not the threads that leak, it's where the flare fits into the fitting. Make sure the flare of the fitting doesn't have any pitting or dirt on them. Your fittings look new so that's probably not it. I have the same problem but it is only a very slight weep, gas doesn't run down the line or pool. I just live with it.

BeansWorld

I'm switching to a fuel line with -8 AN fittings, this will match my fuel line inlet. Now I won't have to worry about leaky flare fittings. I'll be driving in three days. Finally.

BeansWorld

I'm finally driving, the new fuel line with AN fittings solved that final leak:




Overall, a great experience. My biggest issue was waiting for a few days for each small Jegs order. We're now running as good as ever with no re-tune required. Thanks for the help Corvette fans!