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1970GroceryGetter View Drop Down
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Post Options Post Options   Thanks (0) Thanks(0)   Quote 1970GroceryGetter Quote  Post ReplyReply Direct Link To This Post Posted: May/15/2021 at 4:26pm
My thought is vapor lock, what kind of shape is your gas cap in? I’d be curious go see if it does the same thing at the same distance and time running off the can. I’m thinking vapor lock, but a weak pump could exhibit as a gentleman above said, but you’d think it would do it more frequently and not take a half an hour to do so. 

-Rudy 
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purple72Gremlin View Drop Down
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Post Options Post Options   Thanks (0) Thanks(0)   Quote purple72Gremlin Quote  Post ReplyReply Direct Link To This Post Posted: May/15/2021 at 5:17pm
My first thought is fuel pump....
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John b View Drop Down
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Post Options Post Options   Thanks (0) Thanks(0)   Quote John b Quote  Post ReplyReply Direct Link To This Post Posted: May/15/2021 at 5:23pm
Thanks for you input
I mounted a electric fuel pump on frame rail
And routed fuel line as far away from heat as I
Can
Ran out of time so I’ll drive it tomorrow and see how it goes 
I’ll post results 
Thanks again everyone 
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Post Options Post Options   Thanks (0) Thanks(0)   Quote Trader Quote  Post ReplyReply Direct Link To This Post Posted: May/15/2021 at 5:31pm
If you still have the "j" steel tube coming off the discharge of the fuel pump that runs up  between the fuel pump and head, and then parallel to the rocker cover - it's likely vapor lock.
Cut the "J" in the vertical section, move it to the drivers side fender as far as you can, and run fuel hose from there to the carburetor keeping closer to the timing cover then the head.
If that has already been done - ignore me, it's likely the fuel pump. 
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Post Options Post Options   Thanks (0) Thanks(0)   Quote FSJunkie Quote  Post ReplyReply Direct Link To This Post Posted: May/16/2021 at 1:53am
It's May and they are in Massachusetts. I doubt it's hot enough there to vapor lock.

Ignition coils and electronic modules do not like heat in my experience. A failing coil or module can run fine until it gets hot. Then it can do anything from misfire under heavy load only to totally shut off and perhaps refuse to restart.

There is a very good reason why my cars that originally had points ignition still do. 
1955 Packard
1966 Marlin
1972 Wagoneer
1973 Ambassador
1977 Hornet
1982 Concord D/L
1984 Eagle Limited
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John b View Drop Down
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Post Options Post Options   Thanks (0) Thanks(0)   Quote John b Quote  Post ReplyReply Direct Link To This Post Posted: May/16/2021 at 9:59am
Update 
I drove for a while with some hard acceleration 
And all seems well
Will drive again later to confirm 
So It was probably either vapor lock or fuel pump
I’m currently running electric fuel pump
May keep for a while and enjoy driving 
If I go back to mechanical pump I’ll try another new one
And do the best I can to route fuel line away from heat
Thanks again everyone 

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Post Options Post Options   Thanks (0) Thanks(0)   Quote PHAT69AMX Quote  Post ReplyReply Direct Link To This Post Posted: May/16/2021 at 11:06am
Word is that Blaser Auto Nash Rambler AMC Parts in Moline Illinois, phone calls only (309) 764-3571  has available ~$47 USA sourced replacement stock AMC mechanical fuel pumps claimed to be better quality than those offshore sourced available from auto parts national chain stores that have many many various issues and problems right out of the box as reported in social media over the past few years...
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Post Options Post Options   Thanks (0) Thanks(0)   Quote troutwilly Quote  Post ReplyReply Direct Link To This Post Posted: May/16/2021 at 11:22pm
Just a word of caution with electric fuel pumps vs mechanical.
When the engine stops running so does the mechanical pump.  Not so with electric pumps.  So if some sort of accident happens and your fuel line gets damaged and you are unable to turn off the key, the electric will continue to pump and you could potentially have a serious fire danger.
The solution is a shut-off switch that deactivates the pump when the vehicle receives a hit/jolt.  There are new aftermarket units.  The junk yard Ford units seem to be popular.  I have no experience with them, yet.
Bill O.
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Post Options Post Options   Thanks (0) Thanks(0)   Quote Buzzman72 Quote  Post ReplyReply Direct Link To This Post Posted: May/17/2021 at 6:11am
Originally posted by troutwilly troutwilly wrote:

Just a word of caution with electric fuel pumps vs mechanical.
When the engine stops running so does the mechanical pump.  Not so with electric pumps.  So if some sort of accident happens and your fuel line gets damaged and you are unable to turn off the key, the electric will continue to pump and you could potentially have a serious fire danger.
The solution is a shut-off switch that deactivates the pump when the vehicle receives a hit/jolt.  There are new aftermarket units.  The junk yard Ford units seem to be popular.  I have no experience with them, yet.

When I worked at the Ford dealers, it was called an "inertia switch." Ford parts guys will be familiar with that term. Ford "basic" part number is 9341, plus appropriate prefix and suffix.


DO NOT, UNDER ANY CIRCUMSTANCES, TRIP THE PLUNGER on that switch! That's what cuts off the fuel pump, and the last I knew, these switches are NOT resettable.



Edited by Buzzman72 - May/17/2021 at 6:14am
Buzzman72...void where prohibited, your mileage may vary, objects in mirror may be closer than they appear, and alcohol may intensify any side effects.
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1970GroceryGetter View Drop Down
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Post Options Post Options   Thanks (0) Thanks(0)   Quote 1970GroceryGetter Quote  Post ReplyReply Direct Link To This Post Posted: May/17/2021 at 7:47am
I had some experience with those switches in late 80’s fords, we hit some potholes on our beautiful always well-maintained Michigan roads in my dads 87 Ford Exp (2 seater escort) and The car basically thought We were in a collision and tripped the switch. That one was resettable, but I wouldn’t be surprised if the newer ones definitely are not. I’m sure they want any “collision” Hard enough to trip that switch recorded, and it wouldn’t be a stretch that they only want the dealer replacing them. I’m not even sure if they tell you where they are located anymore. In my at the time roughly 10 year old mind, I recall this one was in or near the spare tire well under the carpet or behind a side panel nearby. We still have potholes like that 30 years later, I think the switches just work a little better! Definitely not a bad idea to include one. Few things in life truly scare me, but at the top of the list is the thought of burning to death..... 

Edited by 1970GroceryGetter - May/17/2021 at 7:49am
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