Model T electric fuel pump.

stickshift

stickshift

Senior Member
When I first got my Model T I had trouble with it stalling. Before it would stall, it would "Buck". Since I live in the foothills, I figured out that it was starved for fuel. I bought a low pressure electric fuel pump (3 psi) and that solved the problem, but if I leave the fuel pump on while idling, I can see gas dripping out of the air horn. It might also be flooding while driving. What can be done to get enough gas to the carb while going up inclines, but not have to switch on and off the fuel pump while driving?
 
Since the fuel is gravity feed, you shouldn't be starving for fuel unless there is a blockage somewhere. Are you using a fuel filter? If you are, that is the problem. gravity feed does not do well with a filter.
 
29spcoupe said:
Since the fuel is gravity feed, you shouldn't be starving for fuel unless there is a blockage somewhere. Are you using a fuel filter? If you are, that is the problem. gravity feed does not do well with a filter.
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The electric fuel pump I installed has a fuel filter on the input side. It's sealed, but it's probably a sintered metal filter. The "T" also came with a transparent paper filter coming off the tank but there's no particles in it. The tank is very clean inside from what I can see with a flashlight. Maybe with the two filters in the fuel line is acting like a restriction. I was afraid of the stories I heard about people backing up hills with model T's due to the lack of gravity flow. My driveway is 1/2 mile long and a change of elevation of 300 ft. It would be dangerous to have to back up that. Maybe I can try this filter. I put one my AA truck, low restriction.
 

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The Fords back in that era were limited on the fuel pressure that the float valve can hold. Hot rodders installed pressure regulators to limit down to 3 psi or so. The float valves that are metal on metal couldn't take much more than that.
 
3 pounds would be too much, good chance of overriding the fuel needle valve in the bowl as you are finding. 1 pound should be more than enough.
 
You could add a hand pump to pressurize the fuel tank only when and only as much as necessary. Requires some creative plumbing and a cap with no hole, and a relief valve somewhere but better than an electric pump over pressuring the system all the time. I would think a rich mixture would occur as well as flooding during periods of low manifold vacuum or when the engine is shut off. My T has the tank mounted up pretty high in the back and I get a drip from the carb with more than 5 gallons in there, which barely registers at all on a pressure gauge. Whenever I put that much in the car I have to shut the valve between the carb and tank when parked to avoid a little gas puddle. My model A with a down draft v8 carb uses an electric fuel pump and the regulator had to be dialed all the way down to barely over one pound of pressure.
The other method, which admittedly I have yet to try, but plan to, is a rheostat or potentiometer in the wiring to trim back the power to the pump and thus reduce the duty cycle and pressure created. I read about it in a tinkering tips and also a ford barn luminary suggested it at one point as well for any early ford. Seems like adjusting the volume and pressure on the fly, based on terrain and traffic would give the optimum service. Good luck and hopefully keep us posted on any changes, better or worse! -Chris, in Boulder
 
29spcoupe said:
The easiest thing to do is remove all filters. If doing this solves your problem, your are done.
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I'll give this a try. Also, keeping the tank above half full should provide some pressure to the carb. Won't cost anything but some fuel line for a straight shot.
 
Stickshift I had the same problem, I live in the Blue Ridge Mountains of Va , my 22 coupe if it got less than half tank would spit spuder, jump ,buck, didn't want the hassel of maintaining a electric fuel pump and I had read in one of the Model T books about pressurizing gas tank with exhaust so I pressurized mine with exhaust and couldn't be happier, now it runs up hill with no problemhttps://youtu.be/smymG4xlRcU?si=lsvKDelpST-8r7V_
 
That’s a very interesting concept Randall. Did you have a muffler shop weld in the threaded spool for the compression fitting? My tank is under the seat, so space is limited above the tank. I have a gas welding setup, I might be able to braze in a fitting. I’ll have a look and see if this will work on mine. So, this is just back pressure between the manifold and muffler? Is it necessary to use stainless steel tubing, or would copper work as well?
 
Thanks Stickshift I did the welding copper will work also I just had stainless laying around, torch welding will be fine, get you a 1/4 pipe coupler and saw it in half black pipe welds better, yes it's just back pressure , one of my T friends just did his 25 touring
 
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