Vapor lock

[41/53dodges]

that would be one of the said "diddle" pumps

[austinsailor]

Don, you say that you don't think it can happen in our flatheads because it never happens in yours. If I used only my 40 Dodge sedan, which I've driven often over the past 7 years, I'd come to the same conclusion. But, buying gas at the same place, driving under the same conditions, the car has never once had a problem, the truck does all the time.

I have absolutely no idea why, but it's real.

[desoto1939]

Would this be the type you guys are using?

ebay 300440946332

Dear Austinsailor.

This is the pump that I have in my 39 Desoto and is the new style that I would recommend.

Rich Hartung

desoto1939@aol.com

[jpwuertz]

When I got my B3B truck it had a 190 degree thermostat installed in it and it would vapor lock on warm summer days especially after it was driven for a while. I change the thermostat back to the 160 degree, which was recommended for summer use, and I no longer have a problem. Keep the heat shield between the manifold and fuel pump will also help.

[Don Coatney]

Don, you say that you don't think it can happen in our flatheads because it never happens in yours.

This issue has been discussed many times on this forum. Follow this link and read all the threads. An air bubble in a pressurized line going to a venteded carburetor will not stop the flow of liquid. The term vapor lock has become a catch all for several problems non of which are true vapor lock on a Mopar flathead engine.

http://www430.pair.com/p15d24/mopar_forum/search.php?searchid=718769

[DollyDodge]

I will add my two cents to the discussion. A few weeks ago I would have said my old truck never vapor locked. When I drove it in the 60s and 70s it never died and always started. My grandfather regulary drove it through Death Valley on his way to Tecopa for work in the summers. I still remember the canvas water bags hanging to the sides of the bed. However, this weekend it was between 105 and 107 locally. I took a couple of my first long (10 miles plus) trips. On one of them I pulled into a friends home and visited, but left the engine running, I pulled out on the highway and got up to about 30 mph and it began to stall, I pulled the choke and before it completly stopped rolling the engine fired again for a while and then went through a couple of cycles of stalling and starting, with lots of pumping of the gas pedal and lots of choke, until it finally ran good. Later durning the day, I took my mom for a ride it was about 107. The truck ran great, we came back to the house it wouldnt start, (used ether and way it went). We went to lunch, and after it wouldn't start again, until a quite a bit of cranking. Mom kept saying I think it is the heat. I suppose she was correct. Something sure was going on whether vapor lock or just a dislike for hot days The last several month the old truck will sit for a week or two but always fires right up. My grandfather always said full choke, and full throttle when cold, it has always worked. Not sure what the hot start flooded start procedures are though. I have an operators manual and I don't remember it giving that info, better go look again!