Carburetor dual feed leaking

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danielb927

danielb927

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I got a new carb and installed it today, its a Holley 670 cfm Street Avenger. I got the dual-feed from Holley, part number 34-150 I think, and it leaks pretty badly. Most of it is out of the back line, the secondaries. I read somewhere that this dual feed is prone to leaking, is there anything I can do without having a machine shop around to re-do the flares, or should I just get a summit kit or use the rubber ones that came with the car?

By the way, let me throw in a recommendation for HeliCoil kits and McMaster-Carr, where I bought mine. Took all of 10 minutes to fix the stripped hole in my intake manifold once I got the right drill bit, and it only would have been easier if I had actually had a tap handle. McMaster got it to me one day after I had ordered it the night before at like 6 p.m. It was a little pricey but I understand the Helicoil kits usually are.
 
Bought a duel feed holley also and it leaked. I took it back to the speed shop and told them the problem and they replaced. The 2nd holley I havent had any issues with.
 
leaking at the inlet on the secondary? or is the fule leaking into the secondarys?
..
1. take wrench and tighten inlet ....not the fuel line inlet nut but the inlet at the fuel bowl...

2...tap rear float....might be stuck from sitting in box..
 
It was leaking from the secondary inlet, not into the secondaries. I was unable to tell if it was leaking from the top, above the inlet, or from the flare fitting.

It leaked from both fittings, got it to where it wasn't leaking from the front anymore. I need to find the right sized wrench for the rear one, then I'll try to tighten it down. I don't think the float was stuck because I have the clear float setting plugs in and it looks to be at the right level, but I'll give it a tap. just tap on top of the bowl?
 
some holleys need a 1" open end wrench to tighten the inlet screw that screws into the fuel bowl

holley uses a thin steel gasket on the inlet...
 
I've had issues with new dual feeds too until I lubed the flare with a little vasoline. Then, with a large wrench on the carb inlet fitting, tighten the flare nut with a flare wrench. The lube allowed me to tighten the nut more and get a better seat against the fitting than if it were dry.
 
I had the exact same issue and just had to put a 1" wrench on the carb side and just tightened the fitting up until I thought I was going to break something, leaking stopped.
 
Just tightened it up, I'll try her again. I bought a flare wrench, but I can't use it because it doesn't fit! Runs into the fuel bowl.

Should I use a new carb gasket since the one I have is pretty soaked with gas?
 
I went back out and started it again, only leaking out of the back one now. Pretty sure it is leaking out of the inlet to bowl joint, not the flare fitting. I tightened it pretty well, as good as I could get it with it off the car and an adjustable wrench but didn't want to strip it. I'll get a 1 inch wrench. Not sure I'll be able to tighten it on the car, but it sure is annoying to take it on and off over and over again. Next step after that will be try some gas teflon on the back half of the inlet to bowl threads, I think. She sure starts a lot quicker than with the thermoquad I had on there before though! looking forward to a fixed car here soon.
 
Thanks LX. I might give those a try, they seem like they'd work a lot better than thin steel gaskets! Why doesn't Holley use these standard??

Also, good to see another FABO guy in Champaign!
 
HA. I didn't even realize you were here in town.

I don't know why they don't use them as the standard deals. They work way way better. Maybe they're more intended for the guys using AN bowl fittings or something?

If you want to swing by tomorrow after work, I have an extra pair of those.

Steve
 
D'oh! Wish I had read that a second ago, I just bought a pair on Amazon. Would have been tough to pick them up anyways since I'll be back on campus for school tomorrow with no car. Thanks for the offer!
 
Oh well. Good luck with it! PM me or something if you're ever stuck on something, maybe I can help.

Steve
 
Got it to work! Put on those nylon gaskets and it still leaked but i hadn't tightened them up enough. I would not recommend this, but I got them tight by turning the flare nut, which tightened the inlet to body connection, and all was well.

By the way, I dropped in a new set of spark plugs (NGK V-Powers). I didn't gap them, but I just wanted to see how she ran around the block. I should probably take them back out and gap them, right? And, if so, what gap? My combo is in my sig, if that changes anything about what gap to use.
 
With a new line you have to tighten it and loosen it as many times as it takes to get it to seal.
Every time you tighten it ,it mates together better then the last time you tightened it.
When it stops to leek it can be taken back apart any time and it will seal back up.
The line is made of a soft metal and when it is crushed together by force it seals up
Make sure you use a 1 inch wrench on the large fitting to hold it while your turning the 5/8 fuel line fitting tight.
 
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