Author Topic: 1967 GT500 carburetor problems  (Read 2798 times)

Jakobs67gt500

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1967 GT500 carburetor problems
« on: November 27, 2022, 01:30:40 PM »
Hi all

GT500 #1739 almost ready to hit the road after restoration.

The car is drowning in gasoline, and my mechanic has tried several options without any luck.
I have cold started it a few times, but dont dare to drive it until the problem is solved.
The carburetors were cleaned and got new gaskets installed.

I consider to replace the carburetors with more modern ones.
Can anybody guide me what is the best option, which still will fit under the original air filter?

Many thanks

Best regards
Jakob

Bob Gaines

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Re: 1967 GT500 carburetor problems
« Reply #1 on: November 27, 2022, 02:06:39 PM »
 I have never seen 4 fuel lines going into the BJ BK carbs before. Modifying the bowls is one indication the carbs have been heavily messed with in the past so who knows what other things have been done inside that may be responsible for the issues. I will let someone else go through the multitude of possible thing or things that could be the cause of your symptoms. Back in the day when they had to be every day transportation we switched out the duel fours for a single carb. Of course today I would advise against the switch unless you plan on doing a lot of pleasure driving and you are not concerned about historical appearance. I would have someone who is used to rebuilding the BJ and BK carbs to go through them so you can get them running right. They will always use a lot of gas . The engine is over carburetor ated for typical street driving to begin with. Spirited driving not so much.  There are some on this forum who specialize in rebuilding BJ BK carbs. You went to the trouble of getting a historical repro coil for the engine but it is installed backwards.There are other small things that have been done that would need to be changed if you are concerned about historical look. PM me and I would be glad to help. 
Bob Gaines,Shelby Enthusiast, Shelby Collector , Shelby Concours judge SAAC,MCA,Mid America Shelby

Royce Peterson

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Re: 1967 GT500 carburetor problems
« Reply #2 on: November 27, 2022, 04:55:47 PM »
Hi all

GT500 #1739 almost ready to hit the road after restoration.

The car is drowning in gasoline, and my mechanic has tried several options without any luck.
I have cold started it a few times, but dont dare to drive it until the problem is solved.
The carburetors were cleaned and got new gaskets installed.

I consider to replace the carburetors with more modern ones.
Can anybody guide me what is the best option, which still will fit under the original air filter?

Many thanks

Best regards
Jakob

Those are wonderful carburetors if restored / rebuilt properly. Your photo shows a multitude of problems in the engine compartment. I would start by sending those carburetors to someone who specializes in them for a complete rework / restoration. Then take Bob up on his offer.
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rhjanes

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Re: 1967 GT500 carburetor problems
« Reply #3 on: November 27, 2022, 06:51:09 PM »
I also wonder what fuel pump are you using? 
What is the pressure being delivered to those fuel lines?  (check the output side of the fuel pump for the pressure).   
I'm wondering about stuck needle and seats in the carbs? (I had one stick close as the car sat in a my hot Texas shop all summer, dried out and the stock system did opposite of yours, it couldn't open the seat and fill the fuel bowl.  There was also an issue with the float.....). 
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roger

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Re: 1967 GT500 carburetor problems
« Reply #4 on: November 28, 2022, 02:21:01 PM »
Another problem may be causing some of your issues. There appears to be the tell tale signs of discoloration in the inside of the air horns, indicating a presence of backfire, which may have taken out the power valves.

honker

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Re: 1967 GT500 carburetor problems
« Reply #5 on: November 28, 2022, 02:59:19 PM »
Just out of interest I read through Jakob's other posts.

This is what this community is all about, those with knowledge helping others out !

Mike

Drew Pojedinec

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Re: 1967 GT500 carburetor problems
« Reply #6 on: November 28, 2022, 04:43:25 PM »
My carb business is booked for about a year…
But if you want to tackle those yourself I’d be happy to coach you through it all.

The care for these is fairly specific, but not much different than any other holley.
I also have some blog posts specifically detailing multicarb ford setups on my page afscarbs.com
Feel free to check them out and also feel free to ask me anything.
I’ve done a few of these setups 😉

shelbydoug

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Re: 1967 GT500 carburetor problems
« Reply #7 on: November 29, 2022, 07:05:49 AM »
My carb business is booked for about a year…
But if you want to tackle those yourself I’d be happy to coach you through it all.

The care for these is fairly specific, but not much different than any other holley.
I also have some blog posts specifically detailing multicarb ford setups on my page afscarbs.com
Feel free to check them out and also feel free to ask me anything.
I’ve done a few of these setups 😉

How do you repair the hole in the secondary bowls where fittings were added?
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Coralsnake

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Re: 1967 GT500 carburetor problems
« Reply #8 on: November 29, 2022, 07:59:32 AM »
There are people that can repair that and make it invisible

Jakobs67gt500

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Re: 1967 GT500 carburetor problems
« Reply #9 on: November 29, 2022, 08:02:12 AM »
I have never seen 4 fuel lines going into the BJ BK carbs before. Modifying the bowls is one indication the carbs have been heavily messed with in the past so who knows what other things have been done inside that may be responsible for the issues. I will let someone else go through the multitude of possible thing or things that could be the cause of your symptoms. Back in the day when they had to be every day transportation we switched out the duel fours for a single carb. Of course today I would advise against the switch unless you plan on doing a lot of pleasure driving and you are not concerned about historical appearance. I would have someone who is used to rebuilding the BJ and BK carbs to go through them so you can get them running right. They will always use a lot of gas . The engine is over carburetor ated for typical street driving to begin with. Spirited driving not so much.  There are some on this forum who specialize in rebuilding BJ BK carbs. You went to the trouble of getting a historical repro coil for the engine but it is installed backwards.There are other small things that have been done that would need to be changed if you are concerned about historical look. PM me and I would be glad to help.

Greatly appreciated bob, I will get back to you

Jakobs67gt500

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Re: 1967 GT500 carburetor problems
« Reply #10 on: November 29, 2022, 08:03:12 AM »
Hi all

GT500 #1739 almost ready to hit the road after restoration.

The car is drowning in gasoline, and my mechanic has tried several options without any luck.
I have cold started it a few times, but dont dare to drive it until the problem is solved.
The carburetors were cleaned and got new gaskets installed.

I consider to replace the carburetors with more modern ones.
Can anybody guide me what is the best option, which still will fit under the original air filter?

Many thanks

Best regards
Jakob

Those are wonderful carburetors if restored / rebuilt properly. Your photo shows a multitude of problems in the engine compartment. I would start by sending those carburetors to someone who specializes in them for a complete rework / restoration. Then take Bob up on his offer.

Many thanks - appreciate the input - yes a messy set-up

Jakobs67gt500

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Re: 1967 GT500 carburetor problems
« Reply #11 on: November 29, 2022, 08:03:41 AM »
I also wonder what fuel pump are you using? 
What is the pressure being delivered to those fuel lines?  (check the output side of the fuel pump for the pressure).   
I'm wondering about stuck needle and seats in the carbs? (I had one stick close as the car sat in a my hot Texas shop all summer, dried out and the stock system did opposite of yours, it couldn't open the seat and fill the fuel bowl.  There was also an issue with the float.....).

Good point thanks, I will get it checked

Jakobs67gt500

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Re: 1967 GT500 carburetor problems
« Reply #12 on: November 29, 2022, 08:04:18 AM »
Another problem may be causing some of your issues. There appears to be the tell tale signs of discoloration in the inside of the air horns, indicating a presence of backfire, which may have taken out the power valves.

Yes fully agree, something did not go well - thanks for input

Jakobs67gt500

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Re: 1967 GT500 carburetor problems
« Reply #13 on: November 29, 2022, 08:05:22 AM »
Just out of interest I read through Jakob's other posts.

This is what this community is all about, those with knowledge helping others out !

Mike

hi Honker - yes 100% agree with you, I have got very good guidance, which is much appreciated

Jakobs67gt500

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Re: 1967 GT500 carburetor problems
« Reply #14 on: November 29, 2022, 08:06:25 AM »
My carb business is booked for about a year…
But if you want to tackle those yourself I’d be happy to coach you through it all.

The care for these is fairly specific, but not much different than any other holley.
I also have some blog posts specifically detailing multicarb ford setups on my page afscarbs.com
Feel free to check them out and also feel free to ask me anything.
I’ve done a few of these setups 😉

Haha, I just sent you a mail, as everybody send me your way - and then I saw this :-) Really appreciated