223 Vapor Lock Issues

[NateTheGreat]

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?

Thanks
-Nate

 

[B RON CO]

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

 

[NateTheGreat]

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.

 

[unibody madness]

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

 

[bubba22349]

You might also try to insulate or move the fuel line (fuel pump to carb) away from excessive engine heat. Good luck

 

[Daves55Courier]

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.

 

[Sanfordson52]

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?

Thanks
-Nate

I know this is an old post, but did you ever get the vapor lock to stop? I am having a terrible time with my 52 F1 223 this summer in NC. I have insulated the fuel line, put on a new fuel pump, and added the bypass filter with a return to the tank. The problem seems to be more isolated in the carb (Holley 1904 copy).

 

[Adriatic Machine]

Are you sure it’s vapor lock? Lots of people having problems with cheap points & condensers flipping out after they get hot.

I run phenolic spacers under my 1904s and never have a problem.

 

[Frank]

I know this is an old post, but did you ever get the vapor lock to stop? I am having a terrible time with my 52 F1 223 this summer in NC. I have insulated the fuel line, put on a new fuel pump, and added the bypass filter with a return to the tank. The problem seems to be more isolated in the carb (Holley 1904 copy).

Vapor lock is a lean condition when the engine is running. Hot-soak flooding is a flooded engine when restarting hot.
Your good improvements would all help vapor lock, as the fuel entering the carb while it's in operation will be cooler. Except the filter fuel bypass, the changes may not help hot-soak flooding though, which is caused by gas vaporizing/boiling in the bowl while the engine is shut off, hot. The vapors are pushed up the vent tube and collect in the bottom of the intake plenum. In severe cases liquid fuel can be expelled into the intake also. Isolating the carb from the intake as Adriatic Machine stated above is a great assist to reduce hot-soak flooding.
If your issue is hot-soak, verify the flapper valve in the base of the exhaust manifold (if so equipped) is not stuck shut, increasing manifold temperature. Or any other potential sources of excessive exhaust back pressure, which will overheat the manifolds.
Late ignition timing increases manifold temps also.

 

[Adriatic Machine]

Yes now I remember. I added the phenolic spacers because it helped the geometry on the dual Offy setup. However I did have some long crank time issues on a hot restart, on hot days. That is fixed now.

 

[Sanfordson52]

Are you sure it’s vapor lock? Lots of people having problems with cheap points & condensers flipping out after they get hot.

I run phenolic spacers under my 1904s and never have a problem.

I have a Pertronix in my ignition. No points or condensor.

 

[Sanfordson52]

Vapor lock is a lean condition when the engine is running. Hot-soak flooding is a flooded engine when restarting hot.
What you are describing sounds like what I am seeing, but it happens while running. The engine acts like it is starving for fuel, pops and crackels, then shuts off. Will not stay running, but will start with the throttle held wide open. Vapor comes from the carb. I have a spacer on there too.