Posted by Matt Wilson [108.162.238.150] on Tuesday, January 04, 2022 at 13:59:46 :
In Reply to: Revisit electric fuel pump posted by Galen [172.70.134.165] on Tuesday, January 04, 2022 at 10:07:13 :
I had a mechanical fuel pump on my '49 Power Wagon and was victim to vapor lock numerous times (I lived in hot El Paso TX at the time). I ended up installing an electric fuel pump right next to the tank with wiring that ran to a simple on-off switch on the dash. I installed a fuel pressure gage and regulator in the line next to the carburetor, as the pressure from the electric pump was somewhat higher than the specs in the manual called for. I also installed a fuel filter right next to the electric pump (I think it was right before the pump),in addition to the filter next to the carburetor.
At first, I only used the electric pump when I had vapor lock (which was frequent), or when starting the truck after it had sat for a couple of weeks, so I wouldn't have to crank for a long time to get fuel to the carb, but then the mechanical pump gave out and I relied solely on the electric pump for many years after that, till I put the truck down for repair of other issues. One thing I will say is that I didn't know about the availability of the heat shield that is supposed to protect against vapor lock, or I might have tried that first. My truck didn't have one on it, and I don't know if it came with one from the factory or not. I don't know how well those shields work with today's fuels anyway. Some previous owner had obviously experienced vapor lock problems too, because they had wrapped the fuel lines near the carb with insulation, but it wasn't enough, as I still had problems, even with that insulation in place. In any case, I was so disgusted with getting stranded on the road that I went the electric route to kill the problem once and for all.
When I install an electric pump as I get my truck revived in the near future, one additional thing I will do is install a mercury switch or some kind of cutoff switch. That way, the pump will shut off in the event of an accident. I don't know much about wiring those in place, but I've read a little about that and I don't think it will be difficult and should be a valuable safety feature.
I do plan to get my mechanical fuel pump rebuilt and will install a heat shield this time. The electric pump will be there mainly as a backup in case the heat shield is not enough, and to use as a carb primer for when the truck sits unused for extended periods. I'm hoping the mechanical pump will be sufficient practically all the time, though.