Gas leaking from weber ADFA

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Zoofly
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Your car is a: 1978 Fiat 124 Spider
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Gas leaking from weber ADFA

Post by Zoofly »

First the good news. My car has been running trouble free for almost 2 years and I drive it weekly. But this morning I went to take it out and I didn't get more than a block from home when the car started running rough then eventually died. There was the smell of gas in the compartment and a small puddle of gas on the street.

I'll leave out the part about finding a place to get it out of the way. It's in a safe and convenient place to work on. Traced the leak to what at first I thought was a bad hose from the top of the fuel filter and into the carb. Turns out the hose was fine. It seems like it must be coming from the carb itself right around that area.

I've had the car since 1990 and the carb has never been rebuilt. Does this sound like the best course of action, to rebuild the carb?
Is this something a guy like me with limited knowledge of carbs can do? Maybe replacing the top gasket is all I need to do for now?

I could also take the carb off and bring it to Allison's since they're just 40 miles from me.

Any advice is welcome.
2020 124 Spider Abarth
2019 Alpha Romeo Stelvio - sold
1977 Triumph Spitfire
2017 Fiat 124 Spider Classica - sold
1999 Jaguar XK8 - sold
1998 BMW Z3 - sold
1988 Pontiac Fiero - sold
PaulC
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Your car is a: 1979 Fiat Spider 2000
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Re: Gas leaking from weber ADFA

Post by PaulC »

Take a look at this.
https://www.mirafiori.com/forum/downloa ... p?id=10642
It's a rebuild of an ADHA but is nearly identical to an ADFA.
Nut124
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Your car is a: 1978 124 Spider 1800

Re: Gas leaking from weber ADFA

Post by Nut124 »

If the engine died due to the excess gas, then the float is stuck down in the bowl or the float needle/seat is leaking or excessive fuel pressure. Remove the air cleaner and start the engine, watch the carb. No fuel entering the carb should be visible above the throttle plates. If the float valve is not working correctly, gas will pour out of the main nozzle onto the throttle plate when the pump is running.

The float can get stuck if the bowl dries empty and the float sinks too far down and gets stuck w the casting.
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Zoofly
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Re: Gas leaking from weber ADFA

Post by Zoofly »

We took the air cleaner off. I have an electric fuel pump so just turning the key without starting the engine the pump starts and fuel was coming out right by the fuel intake nozzle. The hoses are all fine so it seems the fuel is leaking from the top gasket. I've ordered the gasket and will replace. If that solves the problem I'll get the car back to my garage and decide to either rebuild the entire carb or upgrade to the DFEV. I live in CA and need to smog the car every two years so if I upgrade I'll have Allison's do the install.
2020 124 Spider Abarth
2019 Alpha Romeo Stelvio - sold
1977 Triumph Spitfire
2017 Fiat 124 Spider Classica - sold
1999 Jaguar XK8 - sold
1998 BMW Z3 - sold
1988 Pontiac Fiero - sold
18Fiatsandcounting
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Your car is a: 1969 and 1971 124 spiders
Location: San Francisco Bay Area

Re: Gas leaking from weber ADFA

Post by 18Fiatsandcounting »

There's a good possibility that it's an issue with the brass fuel inlet line into the top cover. Sometimes they get loose and leak. Looks just like a leaking hose. I've seen people fix them by cleaning up the connection and sealing with epoxy, and this does seem to work. The better option is to have it properly repaired, or find another float cover.

-Bryan
Nut124
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Joined: Wed Oct 25, 2017 6:39 pm
Your car is a: 1978 124 Spider 1800

Re: Gas leaking from weber ADFA

Post by Nut124 »

Zoofly wrote:We took the air cleaner off. I have an electric fuel pump so just turning the key without starting the engine the pump starts and fuel was coming out right by the fuel intake nozzle. The hoses are all fine so it seems the fuel is leaking from the top gasket. I've ordered the gasket and will replace. If that solves the problem I'll get the car back to my garage and decide to either rebuild the entire carb or upgrade to the DFEV. I live in CA and need to smog the car every two years so if I upgrade I'll have Allison's do the install.
It is not the gasket. Did you read my post. Gas is leaking past the float needle. Float is stuck down, bad needle/seat or excessive fuel pressure.
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Zoofly
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Re: Gas leaking from weber ADFA

Post by Zoofly »

When I get a chance I'm going to take off the top of the carb and look into what you all have suggested. I don't know much about carbs but with the help here and youTube videos etc, I should be able to get it going. Hopefully. :)
2020 124 Spider Abarth
2019 Alpha Romeo Stelvio - sold
1977 Triumph Spitfire
2017 Fiat 124 Spider Classica - sold
1999 Jaguar XK8 - sold
1998 BMW Z3 - sold
1988 Pontiac Fiero - sold
Nut124
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Joined: Wed Oct 25, 2017 6:39 pm
Your car is a: 1978 124 Spider 1800

Re: Gas leaking from weber ADFA

Post by Nut124 »

Google weber float adjustment
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Zoofly
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Re: Gas leaking from weber ADFA

Post by Zoofly »

Wanted to conclude this post by saying the problem was a stuck float, just as Nut124 described. I also put in a new top gasket and the fuel leak is no more. :) Thanks for the help.
2020 124 Spider Abarth
2019 Alpha Romeo Stelvio - sold
1977 Triumph Spitfire
2017 Fiat 124 Spider Classica - sold
1999 Jaguar XK8 - sold
1998 BMW Z3 - sold
1988 Pontiac Fiero - sold
18Fiatsandcounting
Posts: 3798
Joined: Fri Mar 15, 2019 11:23 pm
Your car is a: 1969 and 1971 124 spiders
Location: San Francisco Bay Area

Re: Gas leaking from weber ADFA

Post by 18Fiatsandcounting »

Awesome, Zoofly, thanks for letting us know!

-Bryan
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