223 Vapor Lock Issues

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223 Vapor Lock Issues

Post #1 by NateTheGreat » Thu Jun 15, 2017 9:20 pm

Alright guys,

So I've tried all of the fixes to try and solve my vapor lock issues on my '61 223 and cannot get this one figured out.

Some specs:

1961 F-100, 223 with the Holley 1904 single barrel.
Electric pump in-line mounted to the inside of the frame rail.
Wix return line fuel filter mounted post electric pump with a return line that goes to the sending unit.
Fuel supply line runs from the filter up the firewall, clear of anything hot.

The symptoms:

Driving during the hot part of the summer, the truck bogs at anything past 1/2 throttle after sitting in traffic for more than 15 minutes. I'm in Albuquerque, NM so the summers can be high 90's, low 100's at 5-6k ft of elevation, neither of which help.

Anyone have any other suggestions to help me get this one fixed?


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Re: 223 Vapor Lock Issues

Post #2 by B RON CO » Fri Jun 16, 2017 6:23 pm

Hi, I,m not familiar with your set up but. Why is there a return line? Do you know what the fuel pressure is? I understand electric fuel pumps push better than they pull, and should be mounted near the tank. Good luck
B RON CO. Still workin' on it!

1933 Ford Pickup - 59A Flathead V8
1966 Ford Bronco - U14 - 170/200 Straight 6
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Re: 223 Vapor Lock Issues

Post #3 by NateTheGreat » Fri Jun 16, 2017 11:22 pm

Thanks for replying.

Fuel pressure is just about 7 PSI from the pump.

I added a return line to combat this vapor lock issue (I've been battling this for some time). The whole point, in theory, of the return line is that I'm never dead-heading fuel into the carb, especially at idle. I should be constantly circulating cool fuel into the pump, keeping it cool.

Clearly, at this point it's not working.

The pump is mounted as close to the tank as possible without being in the cab.

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Re: 223 Vapor Lock Issues

Post #4 by unibody madness » Fri Jun 16, 2017 11:46 pm

Try restricting the return line a little to insure enough flow to the carb. Check to make sure your heat riser valve is not stuck closed, try a phrenolic spacer under the carb

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Re: 223 Vapor Lock Issues

Post #5 by bubba22349 » Mon Jun 19, 2017 1:03 am

You might also try to insulate or move the fuel line (fuel pump to carb) away from excessive engine heat. Good luck :nod:
A bad day Drag Racing is still better than a good day at work!

I am still hunting for a project car to build but with my current low budget it's not looking so good. My Ex- Fleet of Sixes these are all long gone! :bang: 1954 Customline 223 3 speed with O/D, 1963 Fairlane project drag car with BB6, 1977 Maverick 250 with C4, 1994 F-150 a 300 with 5 speed.

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Re: 223 Vapor Lock Issues

Post #6 by Daves55Courier » Sat Jul 01, 2017 1:01 am

Are you sure you are not flooding out? My223 with holley 1904 rebuild kit inlet needle and seat won't handle anywhere near 7PSI. More like 2.5 PSI max at idle speed. Any pump you get today will overflow a holley 1904 whether you have electric or new mechanical replacement pump.
I tried to use pressure regulators and they blew sky high. It ended up miraculously working out well after I installed a Mopar bypass fuel filter and used it to run a bypass/return line back to the gas tank. I put an orifice in the fuel line immediately ahead of the carb inlet to create backpressure in the inlet line forcing the bypass line to fill and begin the return.
Unibody madness has excellent suggestion with the phenolic spacer under carb to keep the heat down. Also I run my engine full open without the heat riser valve in the exhaust manifold because I don't trust that old junk. Engine will run fine after it warms up. Just gotta use a little choke to start up and I usually push the choke knob back in after engine has run for a minute.

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