Fuel leak check valve

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Ken71Twister

Ken71Twister

FABO Gold Member
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I just put a remanufactured carb in my 1971 318 engine.

I’ve had a recurring problem with fuel leaking at the fuel line/check-valve connection. It seems that, in the past, it has been a trial and error cycle to tighten the nut stop the fuel leak. I’ve had this happen in recent years with two different fuel lines and two carbs. I find myself having to tighten way past my comfort level. I worked hard with latest fuel line to use a tubing bender to get good alignment between fuel line and the check valve carb connection. It still wants to dribble gas when pressurized. For the record…the problem is not the float - it happens where the brass connector presses the flanged stainless steel fuel line into the check valve.

I inspected the flange on the stainless steel tube and it appears to be smooth and scratch free. The check valve and gasket are new.

Anyone else experience this and do you have a suggestion on how to correct this?
IMG_1297.jpeg
 
SS lines are notorious for being hard to seal.
There are copper inserts that might help.

What carb do you have?
 
By the way, you did double flare, didn't you? I can't tell you how many leaks I've fixed where all that was wrong was that the owner had single flared the line.
 
There is a reason soft steel Bundy tube is used for brake/fuel line.......rather than rock hard s/s.
 
I didn’t do the flare on the fuel line. I bought a pre-formed fuel line that already the the flare. As I recall - it came with fittings on both ends.
 
I have more trouble with this joint sealing to the carb, rather than the tube to the fitting.

Screenshot_20240307-222432.png


The stock s shaped tube makes no sense.

It puts a counter clockwise force on the fitting to the carb. This tends to loosen that fitting.
 
Take one wrench on the fitting in the carburetor and the other on the fitting on the line and tighten the CRAP out of the line fitting going into the carburetor fitting and then back it out and do it again several times. This will mate the flare fittings together and allow them to seal.
 
Ken71Twister said:
Yes…. Check valve. Today’s carb is fresh out of the box. I’ve had this same issue over and over. A fuel leak that close to the exhaust manifold is scary.
Click to expand...
It's not a check valve by definition. It's the needle and seat.
 
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