Vapor Lock 200 in line six

I have a 1966 Mustang with the 200 inline 6 with the autolite 1100 It will stall coming to a stop sign, die when trying to accelerate, hard starting after sitting 10 -15 minutes after normal operation. I rebuilt the carburetor and it seamed to be ok. Took it for a drive today and acting up again. The fuel line between the fuel pump and carburetor is extremally hot and I can hear fuel in carb bowl boiling. When I first rebuilt the carb a week ago the fuel line was much cooler.

Stock with canister filter, live in North Florida low 90's, factory thermostat.

I have ordered braided fuel ine to replace metal fuel line from fuel pump to carb. also looking at electric fuel pumps. Would you use the electric with the manual one or without. The manual one is new.

wicked93gs said:

I wouldn't worry about the factory metal fuel line...it isn't causing your issues(they use metal fuel lines even on cars that came out of the factory yesterday). Braided stainless should only EVER be used where a flex section is needed, and only in high pressure EFI applications...the thing they don't tell you about braided stainless is that it makes a very good hacksaw on anything it touches. Regular old steel brake line is the best for all hard sections.

I have heard that electric pumps will help a lot with vapor lock....but they aren't the cause of the issue...if you fuel is getting that hot, the ony possible reason is that your engine is overheating, or close to it.....this is an engine cooling problem is my gut feeling.

Click to expand...

Has new water pump and thermostat, however the radiator appears to be original so I will check that out first.

I have attached the pic's

I got the car in January after getting it home it developed a loud clicking noise (lifer) I thought it ran ok but seemed to be lacking power yes I know it’s a 6 but I have had them before . So I pull head lifers look good cam also ok push rods as well. Sent the head out to be checked small crack (oh no). There’s not a Re manufactured head anywhere except the guy in California wanting 1000 plus shipping (ouch). Found a used one in NC. Had head rebuilt installed with new water pump thermostat 160 rebuilt carburetor. So today I put a spacer under the carburetor and ran it for an half hour to 3/4 in my garage with a temp gauge in the top of the radiator got up to 200 with cap off fuel line hot. Turned off an it spit up a couple of times. That’s my story.

All the pictures I see on line shows metal fuel line.

Vapor lock and or fuel boiling due to the fuel in todays market boils at a much lower point. My fuel line was so hot your could not even touch it for more than a second. Here's what I have found at this point and the thing I have done.
1. Rebuild the carburetor (helped lower the temp of the fuel line but did not totally fix the problem), Purchased the carb kit from Mikes carburetor. Watch his video's on line.
2. Check the radiator for proper operation. I found mine was circulating but had a lot of blocked tubes due to age. replace the radiator more consistent operating temperature.
3. I installed a phenolic riser insulator raising the carburetor 3/8 of an inch. They also come in 1/2 depending on your clearance. (purchased on Ebay)

All three of these really helped but still not a 100 % fix. So after searching all over the internet and speaking with life long Ford mechanics I ran across you tube videos on vapor lock. I found that in the 60's and the 70's that Ford, Dodge, Plymouth and other used a vapor separator in the fuel line just after the mechanical fuel pump. This returns the access fuel and vapor to the fuel tank allowing a Constance flow of fuel preventing over heating of the fuel. These cars came with a return line to the fuel tank from the factory. This is the same as today with fuel injection has return lines to the fuel tank. This all made since to me so I saw a video of a guy drilling a hole in the sending unit and JB welding it in (not sure I wanted to do that) fixed his problem 100%. So I went on the hunt and found the WIX 33041 vapor separator. I also found out the Ford used three different ones. They had .04, .06, and .08 orifices. The Wix 33041 has a .06 orifice in it and was used on 70 chevys. I also read about electric fuel pumps electric fans but this made the more since to me. I found on EBAY a fuel sending unit for 64 - 68 Mustangs with a 1/4 inch return line built in with a check ball only allowing fuel and vapor to return to the tank sold by MCM products. They also sell them on Summit racing but are twice the price. I also ordered 1/4 aluminum fuel line from Speedway racing parts and the filter from O'reilly auto parts.

Fuel sending unit 39.50
Vapor Separator 8.00
Fuel line 15.00
I will be installing this this coming Tuesday when my buddy's lift is free. I have 100% confidence this will be the cure!!
Will update soon!!