Johnboy Posted August 20, 2021 Report Share Posted August 20, 2021 Hi want to put an electric fuel pump on a friends 1947 Dodge 6 volt positive ground. Does anyone know what pressure pump I should use. Quote Link to comment Share on other sites More sharing options...
DJK Posted August 20, 2021 Report Share Posted August 20, 2021 I have the Carter P4259 on my 52 Cranbrook, no regulator, no issues, 6 psi. I did install an inertia switch in the trunk and a switch on the dash to turn the pump off to drain carb to prevent hard hot starts, works great. I also rebuilt the carb with new needle and seat. Quote Link to comment Share on other sites More sharing options...
Sam Buchanan Posted August 20, 2021 Report Share Posted August 20, 2021 (edited) Same here except no dash switch. Pump is located on frame near rear axle. The polarity of the car makes no difference, a pump can be wired either way. The inertia switch is a personal decision, I ran the pump for a year before deciding to install one. Mine is on the firewall. Edited August 20, 2021 by Sam Buchanan Quote Link to comment Share on other sites More sharing options...
Johnboy Posted August 20, 2021 Author Report Share Posted August 20, 2021 Many Thanks for the fuel pump info. I located one on ebay 4-7 pounds of pressure 6 volts positive ground. Quote Link to comment Share on other sites More sharing options...
Local2ED Posted August 21, 2021 Report Share Posted August 21, 2021 Is the inertia switch from a specific car or are they universal? Can the mechanical fuel pump pull fuel through the electric or is it eliminated? I would like to install an electric just for priming the carb after long periods of sitting. Thanks. Quote Link to comment Share on other sites More sharing options...
1949 Wraith Posted August 21, 2021 Report Share Posted August 21, 2021 4 minutes ago, Local2ED said: Is the inertia switch from a specific car or are they universal? Can the mechanical fuel pump pull fuel through the electric or is it eliminated? I would like to install an electric just for priming the carb after long periods of sitting. Thanks. If you want to use an electric pump as a primer you need to install a pulse style like the Airtex brand. The Carters shown above are excellent for stand alone pumps, but your mechanical pump can not draw fuel through the Carter style of pump. 1 Quote Link to comment Share on other sites More sharing options...
DJK Posted August 21, 2021 Report Share Posted August 21, 2021 I eliminated the mechanical pump, the inertia switch is from a Ford Ranger out of a pick a part yard. Quote Link to comment Share on other sites More sharing options...
Sam Buchanan Posted August 21, 2021 Report Share Posted August 21, 2021 1 hour ago, Local2ED said: Is the inertia switch from a specific car or are they universal? Can the mechanical fuel pump pull fuel through the electric or is it eliminated? I would like to install an electric just for priming the carb after long periods of sitting. Thanks. The switch is Ford but there are also generic ones available. Here is the Ford switch I used: https://www.ebay.com/itm/233966503511?fits=Make%3AFord&epid=1817778782&hash=item36797d8657:g:uLIAAOSwzIVZcyS4 I have mixed feelings about the inertia switch, not fully convinced it is really an advantage. It creates a single point of failure in an electrical pump only system. I wired mine with male-female connectors where if it fails open I can unplug the wires and replug them bypassing the switch but it has been reliable so far. If in a minor accident, just reach over and turn off the key and the pump stops. If in a major crash in our old car......it probably won't matter...... I eliminated the mechanical pump...why keep it? 1 Quote Link to comment Share on other sites More sharing options...
Sniper Posted August 21, 2021 Report Share Posted August 21, 2021 56 minutes ago, Sam Buchanan said: It creates a single point of failure in an electrical pump only system. Everything in the electrical fuel pump system is a single point of failure. You only have one pump, there is only one wiring setup to it. There is only one fuse and relay feeding it. I would not worry overly about the inertial switch, Ford has been using that basic design since at least the 80's. Quote Link to comment Share on other sites More sharing options...
Sam Buchanan Posted August 21, 2021 Report Share Posted August 21, 2021 (edited) 1 hour ago, Sniper said: Everything in the electrical fuel pump system is a single point of failure. You only have one pump, there is only one wiring setup to it. There is only one fuse and relay feeding it. I would not worry overly about the inertial switch, Ford has been using that basic design since at least the 80's. I'm not worried about the switch, I have a method for quickly bypassing it. Guess this goes back to my aircraft building background where we try to eliminate as many single-point failure modes as possible. But the most dangerous single-failure point in our cars is the nut holding the steering wheel....... ? This guy had it figured out a hundred years ago: You know you've achieved perfection in design, not when you have nothing more to add, but when you have nothing more to take away. --Antoine de Saint-Exupery Edited August 21, 2021 by Sam Buchanan 1 Quote Link to comment Share on other sites More sharing options...
Bbdakota Posted August 21, 2021 Report Share Posted August 21, 2021 (edited) 3 hours ago, 1949 Wraith said: Edited August 21, 2021 by Bbdakota Deleted comment. Was thinking of the wrong car I had an electric pump on Quote Link to comment Share on other sites More sharing options...
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