Electric fuel Pump

[64V-K7]

The pump is mounted to the frame rail right behind the front seat. Is that too far from the tank?

Not too far... the tank would feed the pump by gravity and thats fine.
There should be a filter between the tank and the pump...

[toddbowie]

There should be a filter between the tank and the pump...

Yes, I'm moving the filter from the engine compartment to by the gas tank.

[studegary]

Not too far... the tank would feed the pump by gravity and thats fine.
There should be a filter between the tank and the pump...

I think that it is too far from the tank. Gravity would only come into play if the tank was nearly full. Think of where the tank is located relative to the frame (other than on an Avanti).

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Yes, I'm moving the filter from the engine compartment to by the gas tank.

I wouldn't move the filter. Add another filter. Some cars with an electric pump originally came with two filters.

[wh22366]

My 63 GT 289 4 bbl has an electric pump. It is by far the easiest starting carburated car I've owned in years

I added a gerotor electric fuel pump to my Hawk (sourced through Randy Rundle) when I got sick of the long crank up. The pump came with a 500 micron filter already plumbed to the inlet side. I removed the mechanical pump, blocked off the port and kept the filter at the engine. Starts soopah!

[toddbowie]

I had to pull the tank to get to the sending unit (no access in the trunk) and there is no venting. There is a small hole in the center of the gas cap. Is the cap vented or is there supposed to be some kind of vent? The FSM says there should be a vent in the filler tube.

[studegary]

I had to pull the tank to get to the sending unit (no access in the trunk) and there is no venting. There is a small hole in the center of the gas cap. Is the cap vented or is there supposed to be some kind of vent? The FSM says there should be a vent in the filler tube.

Vented fuel filler cap. Check that it hasn't been either plugged up or the cap replaced with a non-vented one.

[toddbowie]

Thanks, that's what I thought. I'll make sure it isn't clogged up.

[56GH]

There's a electric fuel pump mounted on my 1962 GT Hawk right near the fuel tank by a previous owner. The mechanical pump opening on the engine block is capped off. My car sits for relatively long times without starting it, so the electric pump is a godsend. The only thing I have to remember is to turn the key on and let it pump for about 30 seconds to fill the carb. The engine starts almost immediately after that. And no vapor lock problems in hot Florida weather!

[bensherb]

I have an electric auxillery pump on my '62 GT. It's a factory pump for a Toyota about $15 on ebay. I mounted it on the frame just forward of the left rear spring. It's just used for priming and is on a momentary toggle switch, so only works when holding the switch on. Works great, no more cranking for several minutes to get fuel into the carb after being parked a week.

When I cut the fuel line to install it the tank was about 1/2 full. It drained ALL the fuel in the tank at that point.

[BILT4ME]

Might want to check the fuel filter and be sure it is on the tank side of the fuel pump.

I disagree with this statement. Fuel PUMPS are designed for PRESSURE, not vacuum. Depending on the TYPE of pump, it may be capable of higher vacuum than others.

What brand / type of pump is on the car?
What is the pump capacity in GPM?
What is the pump PRESSURE rating?

First:
The carbs used on the Studebakers typically like no more than 5 PSI of fuel pressure at the inlet to the carb. If it is higher, it can push fuel past the needle and seat (held closed by the float) and cause flooding. if it is much lower, then you may run out of fuel at speed.

Many of the Rochester carbs used on GM products are rated for 7 PSI. Part of that is because there is a sintered filter at the inlet to most of those carbs and the additional pressure is used to help overcome a dirty filter, as it is a restriction in the line.

Second:
As far as the FILTER goes, the filter should be located as close to the CARBURETOR as possible. This is because the pump can PUSH fuel through a filter better than it can suck fuel through a filter. Most of the electric fuel pumps have an inlet "sock" or "screen" in the inlet side of the pump. This is to keep the suction pressure (vacuum) to a minimum in order to keep flow to the pump as uninterrupted as possible. If there is an actual filter between the pump and tank, then the pump has to suck the fuel through the filter media and that increases the resistance. More resistance = less flow.

The purpose of the filter is to remove the particulate so it doesn't get lodged in the jets. The fuel PUMP does not have the tiny holes like the jets in the carb and it won't care what it sucks and pushes through. The filter should be as close to the carb as possible because there can be particulate in the line (rust, debris, whatever) all the way up to the carb, and reducing the distance between the filter and carb reduces the risk of intrusion.

Third is the pump capacity in GPM.
If you assume that the car only gets 12 MPG (Assume the lowest MPG for the most accurate requirement) at 60 MPH, then you will need to have a MINIMUM requirement of 5 GPH (=0.08333GPM). We're not driving race cars here, so the amount of "free flow" fuel is not going to be an issue. More is not necessarily better. Choosing a random cheapest pump from Summit, it lists 4-7 PSI and 35 GPH free flow. I once used a Holley pump designed for 70 GPH and 15 PSI on a Chevrolet and wondered why I kept ruining fuel pumps. I had to regulate it back to 7 PSI and only needed about 35 GPH maximum.

Fourth is the type of fuel.
My Stude HATES ethanol fuel and it vapor locks when the engine temp hits 245°F. Just running the ethanol (max 10%) makes the car start harder and get worse gas mileage and have less HP than when running plain non-ethanol gasoline. The alcohol portion vaporizes at a lower temperature and thus causes vapor lock earlier in the cycle, making thing more difficult.

Having driven our car on the Hot Rod Power Tour two years, there are a number of states that do NOT sell non-ethanol fuel. It makes it harder to enjoy it, but you must be very aware of what you're doing and watch your temps. The electric fuel pump DOES help offset that issue because it is more likely to keep the fuel at a higher pressure. The higher the pressure, the higher the boiling point and the less issue with vapor lock.

Fifth:
The routing of your fuel lines can also play a role in the amount of vapor lock. The factory lines on my 59 Lark run up the inside of the right frame rail, next to the RH exhaust manifold, then cross over near on the front crossmember on the front of the engine to the fuel pump, then up the left side of the front of the block to the carb. If you could route your lines on the OUTSIDE of the frame and then down from the top, (this brings its own challenges) and /or insulate the lines using a rubber hose over the lines to keep the fuel temps as low as possible until it reaches the carburetor, it would be worthwhile. Some of the old school racers would use a coffee can and route the fuel through copper coils of line wrapped inside the can and fill the can with ice to improve the fuel density for racing. This is a short-term solution though.

The newer fuel injected cars run MUCH higher fuel pressure (40-60 PSI) because it is required by the injectors. This inherently lowers the risk of vapor lock due to the increase in boiling point. The free flow capacities are also higher because they adjust for higher pressures and Wide Open Throttle (WOT) conditions.

[TWChamp]

The instructions for my electric fuel pump insist on the filter before the pump, so you don't get damaging dirt in the rotating pump parts. That's the way I install my filters, and have no pumping problems, but of course I do have the usual problems with today's gas the boils way too quickly, and causes hot restart problems. I'm going to try more insulation around the fuel lines and carb. Some people report that adding a quart of diesel fuel to a tank of gas helps, and I'm going to give that a try also.

[bensherb]

I put a 1" thick phenolic spacer under my carb, blocked off the exhaust crossover in the intake manifold, and removed the seal between the hood and cowl (replaced it with 5 rubber blocks to suport hood). Between those things, it dropped under hood and carb temp and took care of fuel boiling in the carb and hard restart. I just use the electric pump to get fuel to the carb after it sits for a week, so I don't have to crank it forever.

[Studejohnn]

If you lose the mechanical fuel pump, it would be tank, filter, electric pump close as possible to tank, filter, and on to carb. Wiring through oil pressure or an impact shut off relay is a must. Don't want that thing pumping in the event of a crash.

if keeping mechanical, then tank, filter, electric, mechanical, filter, on to carb. The outlet valve in the mechanical will act as a check valve and prevent back flow. Make sure the electrical allows flow through it when shut off. Not all do. As many do, use a toggle/momentary switch on the electric for priming. Easier starts and much easier on the starter. Then let the mechanical take over.

just two of many ways to do it.

[Buzzard]

I concur with Marks' comments in post# 25.

The carbs used on the Studebakers typically like no more than 5 PSI of fuel pressure at the inlet to the carb. If it is higher, it can push fuel past the needle and seat (held closed by the float) and cause flooding. if it is much lower, then you may run out of fuel at speed.

I live off the grid and use a lot of electric pumps on old military stuff as well as Studebakers(US6 and Weasel). I use a Holley Fuel Pressure Regulator which can be adjusted down to 3-5 psi as needed as most old carbs won't take the pressure at the seats.
I'm also blessed with with having available Premium Fuel with NO ethanol(nor road tax!). We have even had fuel boiling issues in the summer in chainsaws etc. Ethanol is a curse.
Bill

[San Diego Ron]

I've been looking here because of same problem, my '62 GT Hawk won't start without a squirt of starting fluid. I installed electric pump with toggle switch to assist mechanical pump only for starting...that made no difference so then put a check valve near carburetor (thinking fuel was running back out) and that also made no difference. Carb has been rebuilt but thinking it is either a bad accelerator pump or a bad float???