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I added an electric fuel pump to aid in cold starts.
Now my machanical pump is leaking and it may take awhile to get a replacement (on back order at Max M)

Would there be a problem to just by pass the mechanical pump and use the electric one?

I was not planning on removing the original pump, just connecting the input and output hoses together and using the electric pump.

Would I need to seal the openings in the mechanical pump?
Would this work until a get a new pump, or it make more problems I’m not thinking of?
I understand the old pump would still be working, but running dry.
Thanks in advance

It should be fine. Others have bypassed the pump when they have had to.

Just need to make sure your electric pump pressure is not too high. If you have a regulator after the pump then should be OK but if not, a 2 to 5 psi pump would match your mechanical but an 8 to 10 psi pump could be iffy. That higher pressure might overwhelm the carb float valve without the resistance provided by going thru the mechanical pump and its internal filter lowering the pressure a bit.

I think it would be better to remove the existing pump and put a blockoff plate on rather than take a chance on the pump breaking up due to no load and over flexing of an already torn diapraghm.

I'd be inclined to remove and store the mechanical pump. Don't trash it! They're getting scarce.


A block off could be easily fabricated,
and removing the pump will prevent any further wear on it. It will also increase airflow in the underhood area and prevent any issues with noise, oil leakage, rubber shedding into the crankcase, etc, related to the pump.

You will lose the vacuum booster function, but for that to work dependably, you'd need to rebuild the pump.

Many modern vehicles use an electric vacuum pump, and adding one of those and a vacuum reservoir would provide better than stock wiper performance.


Ive had a number of cars with vacuum wipers and no booster. I've found them adequate for most driving situations.

I believe that Packard recommended a fuel pump pressure of 2.5 to no more than 3 lbs. Most electric pumps will exceed that. I'd want to use a good pressure regulator in conjunction with an electric fuel pump.


Excess fuel pressure will tend to cause difficulties with carburetor flooding and poor fuel mileage due to inconsistent regulation of fuel level in the carburetor bowl.

Most of us are not driving our Packards in poor weather anyways. So wipers not a huge deal.

There's two problems pressure and delivery/flowrate when you install an electric pump on a formerly mechanical. Most of what's out there is made for FI and is too high pressure and recycles the excess flow to the gas tank w/ or w/o a regulator. Some are internally/self regulated.
It's probably obvious that yours has too much pressure, if it ruptured the mechanical's diaphragm or leaks out the housing. There is one I used(12VDC) that's made for carb cars that has the right pressure and flow. I'm not aware of 6Vs. It's a bit noisy but works in a full replacement where mechanical is bypassed. It's also wise to go the extra mile and do the electrical upgrade(relays,breaker, and multi-pole pressure switch) to avoid the pump running when it shouldn't. Not enough amperage to run off the ignition.
That info will come with the pump usually and there's a few good online help. Just putting on a manual switch is dangerous.

Howard is correct. If you choose a pump please make sure it falls within the mechanical pump pressure. The MoTors manual for a 22nd Series mechanical pump is listed at 3/3/4 PSI. My car has the mechanical pump bypassed. It was that way when I bought it. The last owner said it was that way when he bought it, and he had the car for 10 years. Its just a small inline pump, no return. I recently tried to lean out the carb, the car is running way too rich. I couldn't make any adjustments. I believe the pump is putting out too much pressure. So this week I'll be putting in a regulator and gauge. Then I'll try to adjust the carb. So I.d put in a regulator and gauge as well. I purchased the two on amazon for $45.00 total.