Vapor Lock

[Old Henry]

Every time a thread starts any where on this topic, there will be those who say that vapor lock doesn't exist.

That was me! For years whenever an old timer saw me stopped on the side of the road they'd say, "Vapor lock, huh?" I'd so, "No it's something else" but could rarely figure out what it was. After one event of frustration and deciding to pour water on the fuel pump to cool it down "just in case" it was vapor lock it started right up. I became a believer and will now install an electric fuel pump to "prime" the mechanical one at those times.

 

[Ross in East Texas]

In 1966 my '39 was my daily driver. I was in college at the time and it was 150 miles from home. I would frequently stop for a Coke or such during these trips and if it was during the warm months, I would have to finish my drink so I could put the cup of ice on the fuel pump to get the engine to start. I never thought any thing about it it was just a way to get going. I removed the side panels in the Summer months which let the engine run cooler as well as the inside of the car. I knew that when stopped the fuel pump would heat soak and vaporize the fuel and the engine would not start until it cooled.
I now have a 6v fuel pump located near the tank for help when needed but usually left off.

 

[Aeroman99]

So old Henry would you suggest that I olny use the electric fuel pump when needed in stead of running it all the time ? I tell ya that little bugger is noisy. It seemed as though the steel fuel line amplified the sound of the pump so I ran rubber tube from the pump up to the mechanical pump and it seemed to quiet it down a bit. Any suggestions on that would be helpful also.
Thanks

 

[Old Henry]

I haven't actually installed the electric fuel pump yet. I have it but am waiting until I absolutely have to install it - next summer. So, I don't have personal experience but I don't see any reason to run it at any time except when the mechanical pump is not pumping. That is what I intend to do and know many that only use the electric pump to prime the mechanical one when necessary. I have also had the thought that with both pumps running at the same time in "series" will add the pressures of the two, 3.5 psi and 3.5 psi, kind of like connecting two 6 volt batteries in series that then creates 12 volts, making the pressure going into the carburetor 7 psi which would overpower the float valve and cause it to flood. But those who run them both at the same time all of the time say that is not a problem. Sounds like that's what you're doing now. Does that flood your carburetor over?

Especially since you are annoyed by the noise of the electic pump, I'd leave it off and just use it when necessary. That's what I'm going to do.

 

[bob miller]

I've found an old advert ford (europe ) in this years vapor lock was already a problem !

 

[Byron Warwick]

My recent "Vapor Lock" happened in October. Merlot stalled and restarted about 10 times. It finally ran for the next mile or so and we got back home. I pulled off the Carb and the fuel pump prior to winter storage. A week later I looked at the fuel pump to drain the gas in the bowl. What I found is the rubber gasket on the glass bowl had swelled and, I think, pulled away at one point and was sucking air. I presume this is modern fuels messing with us old car guys again. I guess I'll go back to the cork gasket. Byron.

 

[Aeroman99]

Well I'm hoping the electric fuel pump will solves my problem with V/L. I also believe Ill install a toggle switch so I can run my pump when needed in stead of full time. I'm also thinking about putting some louvers in the fender wells to allow more air on the motor while driving down the road. Kind of like ram air to help keep the motor cooled down some. Maybe even add a electric fan on the radiator. Some of my winter projects.

 

[Old Henry]

the rubber gasket on the glass bowl had swelled and, I think, pulled away at one point and was sucking air. I presume this is modern fuels messing with us old car guys again. I guess I'll go back to the cork gasket. Byron.

It's not just modern fuels. The last time I drove "Old Henry" in 1975 (before resoring him recently) the settlng bowl gasket was gone so I cut one out of a rubber inner tube and thought it would do. Well it got me to where I was going before doing just what you described. I had to find a piece of cardboard and cut a gasket out of it to get home. Inner tube rubber will soak up and be deteriorated by any gasoline, not just "modern fuels." The true genuine cork gasket is the only thing that really works long term (of course, cardboard works too - short term - very short term.)