Autolite 4100 leaking gas - Vintage Mustang Forums

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post #1 of 3 (permalink) Old 01-28-2013, 12:59 PM Thread Starter
Join Date: Feb 2010
Location: North Dallas
Posts: 95
Autolite 4100 leaking gas

I purchased a rebuilt Autolite 4100 recently... have not had much use since my car is still in primer with no windows... but I have taken it around the block and it love the power over the 500cfm edlebrock I had in it.

I recently changed the spacer to one that has a pcv intake. Upon getting things going again, I noticed gas pooling in an area on the carb adjacent to the fuel inlet needle.

I am not exactly sure the purpose of this circle... there is one on each bowl right next to the fuel inlet needle that sits within the bowl. Is this an area for a freeze plug that may not be sealed that well? Can I fill this circle with JBWeld?

I have reached out to the rebuilder of this carb and he has yet to reply to my email.

Over the weekend, I converted the automatic heat choke with a manual style... after running it a bit on the rich side, I really noticed the gas leak.

If you look to the left of the circle, you will see more gas. You can see what looks like a raised line in the corner... I cannot tell if there is gas also coming from it, but it kind of looks like that to me.

Not sure what to do? is this something that can be repaired if it is actually leaking from that spot as well?

Also, What should I expect from the carb rebuilder? Granted it has been some months since I bought from him... but I do not see how I could have caused this issue? Or if this is just the roll of the dice with these old carbs?

Thoughts, suggestions welcomed.
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post #2 of 3 (permalink) Old 01-28-2013, 01:07 PM
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Join Date: Nov 2001
Location: Medina, Ohio
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Its hard to say from pics, but that carb has had a rough life. There are hammer marks and gouges all over. I wouldn't be surprised if that plug was poorly installed and leaking. If its only the plug, the hole could be drilled, in a machine shop, up to the next larger plug. If there is a crack in the carb body, its unrepairable.
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post #3 of 3 (permalink) Old 01-28-2013, 01:45 PM
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Join Date: Mar 2010
Location: LI NY
Posts: 4,313
those are plugs to seal off the drillings used in the engineering process.

sounds like yours is not seated or was rounded out by an over ambishous carb tech..

imo the carb dont look all too bad.

that plug can be fixed by either reinstalling a new one or have it threaded and pipe pluged then use some plumbers dope on the threads
not JB weld or any kinda of liquid fix for that.

1970 Mach 1 San Jose built Dec 23 1969. Marti says 1 of 7. Purchased in 1987. Original family owner of the powertrain 351C 2v FMX.

1993 GT 11,000 miles, Built 2-12-93 Auto, 3:27 Axle, cloth, sunroof. Untouched except for rubber and battery, Purchased new 8-3-93. still has the factory windshield fluid and new car smell.
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