I would try changing the fuel filter and maybe change out that rubber line to hard line. just my 2cents

 

Hey BTodd,
Welcome Aboard! Nice looking truck - You don't see many with visors these days. You wouldn't think San Francisco would present many vapor lock issues unless you live out past The foothills a bit.

We had a vapor lock issue with our '50 initially but it get's pretty hot here in Texas. You could here a whistling coming from the gas tank & when you took off the cap air rushed in/out. We went with a vented gas cap & added more venting to the tank itself. There weren't any issues in the winter only when things started to heat up in The Spring.

Good luck over there in the Bay Area.

Ben in Austin
1950 F1

 

I agree that wood is not a good conductor I did not indicate in my post why the clothespins work, only that it did work for me (on a steel line). I do not believe that I used enough clothespins to be an effective insulator. I do not know why the clothespin trick works (at least on steel line) but am suspicious that they create a more turbulent airflow adjacent to the fuel line.
On that cross country trip it was hot and I was flat towing a Model A (see pix in my gallery). I tried a number of things before stopping and having an old timer in a gas station offer the suggestion. I did not initially buy into his suggestion. He indicated that he use to keep some clothespins at the station but did not have any then. I remained skeptical until he offered to go home and get some. At that point I told him that I would take him up on his offer. I took down his name and address promising to tell him how it worked out. In a note to him after the trip, I enclosed a package of new clothespins for the "next guy"!

 

Thanks. Yes. I have replaced the fuel filter, the old one was metal and I've replaced it with plastic and can see that it looks clean. Should have mentioned that in the original post.

 

Thanks. Yes, fuel filter done. Interesting thought on the steel versus rubber lines.

 

Thanks. I'll check into that. I can see how that would cause or contribute to the same kind of problem.

 

Thanks Ben! I'm about 75 mi north of SF in one of the hottest parts of Sonoma County. Still not as hot as Austin, I 'm guessing, but yeah, 90's and up pretty often. I'll check into the tank venting. Seems like it could be a key factor.

 

I mentioned hardline v.s. rubber because I've heard of rubber lines having problems and having reduced flow.

 

Thanks. That makes sense to me.

 

An easy way to check for fuel tank venting issues is to loosen the filler cap.

 

Would the best way to do that be to start it and run it for a while then open the cap and listen for pressure release?

 

Hey BTodd,
You'll know if you have a venting issue. Just drive around when it's warm/hot for about 10 minutes - then pop off the fuel filler cap.
If you get a loud rushing of air - that's it. A vented cap doesn't cost much <$10.

It will stink up your garage more than a closed cap. After complaining from the female side of the family we ran a vent to a charcoal canister.

Ben in Austin
1950 F1

 

If you have a venting problem it won't be pressure....it will be a vacuum. The rushing sound will be air going into the tank. If the vent is not working, the tank will pull a vacuum after you run it for a while....that vacuum eventually matches the suction of the fuel pump and fuel stops flowing.

Dan

 

I'll check it out. Thanks. My truck's in a tent garage away from the house, so no worries on the aroma.

 

Yep. That's what was thinking, but bad choice of words on my part. Thanks.