The carb was having issues, so I removed the bowls, sprayed the bowls and body with carb cleaner, and blew out with compressed air. I reassembled with new needles/seats and their gaskets, new gaskets between bowl and metering block and body, and new accelerator pump diaphragm/umbrella, and new bowl screw gaskets. I dry adjusted the float to 7/64 (as Holley instructs for side-hung nitrophyl floats). I removed the float and checked it. Not only was it empty but it floated. The leak is pretty steady. It appears to be coming from beneath the bowl in the vicinity of the accelerator pump—I put a straight edge to the pump cover but it seems fine. I also inspected the diaphragm but could see nothing amiss.

I did not replace the base plate gasket or power valve.

I've put a straight edge to the metering block and body. Looks straight. Guess I'll tighten the bowl screws a bit more and see what happens.

Any advice or direction would keep me from seeking hair replacement.

JamesC

 

Model 4160 with a transfer tube between the bowls correct? That was my first carb and I experienced a nasty leak from a pinched O-ring on the tranfser tube. Not sure if that helps but I'd hate to see you needing a toupee.

 

No problems with the tube, skinny. I'll throw the carb back on on Thursday. Perhaps simply tightening the bowl screws will be enough. Baring that, I'm at a loss.

JamesC

 

Sounds similar to what I experienced at the beginning of last year. I decided to clean out my Holley street avenger and wound up with a leak under the bowl as well. For me it turned out that the accelerator pump diaphragm cracked and was leaking.

Since you replaced all the gaskets and pump I'm wondering what is going on as well.

I have had to give the bowl screws and extra tug in the past at times after changing jets reusing the "Reusable" bowl gaskets on our 67.

 

I've traced the leak to the lower pass side bowl screw. Apparently, the nylon gasket isn't sealing. I've cleaned the bowl surface and played with the gasket, but so far no cigar. Tips?

JamesC

 

[QUOTE=JamesC;5730215]I've traced the leak to the lower pass side bowl screw. Apparently, the nylon gasket isn't sealing./QUOTE]

The nylon gasket was sitting on a bit of a shoulder on the bowl casting. I bought a nylon gasket at Ace, then filed it to fit the bowl screw. To get it off the shoulder, I went smaller on the outside diameter of the gasket than the Holley piece. Eventually, I got it to seal.

I set the floats, idle speed screws and curb idle. Oh, I'd previously adjusted the accelerator pump arm which cured a bog/hesitation I'd been experiencing.

The weather has been an issue since Thanksgiving when my dilemma began. All's running smoothly again.

JamesC

 

With your hair intact.

 

Lol. That's the final triumph.

JamesC

 

Good to hear you got it fixed.

I don't worry about pulling my hair out anymore, I lost most of it awhile back. LoL

 

Actually, I wanted to do a bit of tuning with jets, power valves and so on, but I'm hesitant after this last debacle.

JamesC

 

Hardly a debacle. At least not by hot-rodding standards. Having a set of valve guides wiped out after 2000 miles due to assembler incompetence , now that's a debacle. (I can't point the finger at anyone but myself.)
Gather up your resources.
Get your tools.
Go to it.

 

You forgot "Gather your wits." As I've gotten older, that's become more difficult.:roll eyes:


JamesC

 

Hey James, since you are going to take the bowl off, might want to see if some on can machine that shoulder area flat so you won't have to mess with the gaskets all the time. A drill press and the right diameter mill bit could even do the trick.

Yea, a little gas leak is hardly a debacle. I wiped out a brand new hydraulic cam back in 2002. I installed it like I had installed a bunch of other cams years ago only to have 3 lobes get wiped out during break in. I used newer oil, soaked the lifters and pumped them up like in the old days and used the break in lube supplied.

Crane replaced the cam and I installed them like instructed, didn't soak them or pump them up, and used Shell Rotella-T to break in the cam.

 

I say "debacle" because the issue begin on Thanksgiving Day and was only resolved a few days ago. Why? The bloody temps were so cold I couldn't get into the garage. Frustrating. Anyway, car show season is upon us and I'm ready to good soak up some sunshine.

JamesC