54 Mercury-Electric fuel pump question.

[Bob from Northport]

I installed a new 6 volt electric pump on my 54 Mercury-256 engine. With it, I installed all new fuel lines. A brand new-not rebuilt-fuel pump. A brand new carburetor-not rebuilt. I have a fuel pressure gauge on the line near the carb.
The engine restarted and runs well. I installed a bypass around the electric fuel pump just in case. When switched on, the pump runs fine, but does not seem to pump any fuel forward, or build up pressure at the gauge. There was an old one on the car that did build up pressure to 3.5 lbs.
Can anyone think of a reason why this new pump does not seem to be pumping fuel?? Other than being a bad pump??
The photo is the electric pump I installed to the rear of the car on the frame.

[fordor41]

install as close to tank as possible. Is bypass just pumping back to the tank? If so will not register on a gauge, just pumping around in a loop.

[miker98038]

^^^^^. The bypass needs a check valve or a shut off valve in it. But I’ve never had an in line electric the mechanical pump wouldn’t suck thru.

[KULTULZ]

A brand new-not rebuilt-fuel pump. A brand new carburetor-not rebuilt.

You did not get rid of the take-off mechanical pump or carb?

If you mounted an electric supply pump to feed the mechanical pump, it has to have a fuel gravity drop to the pump or an in-tank pump. An electric pump is designed to push not pull. The elect pump needs a pre-filter.

Is it a primer or supply? If primer, it should have a flow-thru rating.

The by-pass circuit needs a one-way valve installed unless used only as a primer.

How is it wired to operate, a toggle switch or ign switch operated (constant hot)?

[Bob from Northport]

fordor41 was right. I removed the bypass and the pump works fine.
Mr. Kultulz- The pump is used as a primer. It is on a toggle switch, not hot all the time.
There is a prefilter behind the pump just out of the picture I posted.
The pump pushes fuel now to 3.8lbs on the gauge. It held pressure even when off till I left the shop.

[KULTULZ]

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MR.KULTULZ ...???

Why do I have a feeling I am about to get served?

Any-who, is the pump an actual primer pump, i.e., it has a flow-thru rating (VENDOR - PN)?

[Bob from Northport]

Yes. The pump is the one you recommended for me from Amazon. The instructions say it is a flow through pump. I just wanted to assist the car when starting. It sits fir about 5 months during the winter here. And is driven occasionally in the summer. As usual your information is always a great help. Thank you!!!

[KULTULZ]

Well, I am not b!tchen here,but there are a few things to consider.

The mechanical pump may experience ethanol fuel separation drawing through a filter (electric pump pre-filter in this instance). Just be aware if it has any problem(s) and keep the board informed of how it does.

Do you take it out occasionally during the winter if the roads are clear?

[Bob from Northport]

I use only non ethanol in this car. Never that crap gas.
No, the car is not driven in the winter. The road where I live are seldom clear. 18 here right now and snowing. Thanks again!!!

[Abe Lugo]

Check the gauge. It might be incorrect for the carb or just not working.

Unplug the fuel line and use the electric pump on into a bucket. Do it before and after the gauge.