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1966 Ford Mustang 302ci engine
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Discussion Starter · #1 ·
Hey guys (gals). I bought my 1966 with totally new 302 engine dream car about 2 months ago. Always loved working on old cars since I was a kid so I aint new to fixing these things. However I have hit a stump and hoping someone can help me figure out what is going on. Engine runs for hours and then starts choking or struggling for fuel after hours of running. Dies and then will not start until engine cools down or a tin of starter fluid is poured into it. It has a 4 barrel Holley electric choke. Im thinking vapor lock issues? I have rebuilt carb and fixed all vacuum issues.
 

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1967 Mercury Cougar XR7
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Fuel boiling does sound like a possibility. Another thing I've seen is crud in the filter causing this; it runs for a time, and gradually sediment and garbage clogs up the filter till the carb can't get fuel! When you stop, the crud falls away from the filter element, and allows it to pass once again - for a while.

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I noticed you have a 5/16" fuel line hose from pump to carb. This is what I have as well and I've never experienced any vapor lock before. However, what you are describing sounds very much to me like vapor lock. I would suggest to resleeve the line with a heat shield material or better get a hard line which is what I want to do to mine very soon.


J
 

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Laugh if you want but in the 70’s vapor lock was a common problem. To solve it we put a wooden clothespin on the fuel line & viola.
Now I know that’s not a viable solution but I thought I would toss that in for fun.
 

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1966 Ford Mustang 302ci engine
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Discussion Starter · #15 ·
Guys. I appreciate all the tips and help. Turns out the fuel pump was faulty, wasn't supplying like it should have, and would intermittent stop pumping gas all together (after warming up and riding for awhile). It also was leaking around diaphragm seam. Checked bowels after it died and saw no gas at all. Replaced the fuel pump with a $38 pump with 4.8 star reviews and it runs awesome now. Noticeable performance and no more dying. The original rebuild fuel pump that went bad was a Holley 12-338. Several bad reviews on this one online.

Guys. I appreciate all the tips and help. Turns out the fuel pump was faulty, wasn't supplying like it should have, and would intermittent stop pumping gas all together (after warming up and riding for awhile). It also was leaking around diaphragm seam. Checked bowels after it died and saw no gas at all. Replaced the fuel pump with a $38 pump with 4.8 star reviews and it runs awesome now. Noticeable performance and no more dying. The original rebuild fuel pump that went bad was a Holley 12-338. Several bad reviews on this one online.
This was the Holley after I pulled apart. It's either the inlet or outlet check diaphragm valve that was issue.
 

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