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Topic: Electric Fuel Pump (again, with a twist)

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Todd W. White

Electric Fuel Pump (again, with a twist)

Quite a regular

Hello to all you fellow Packard owners. I have read every post on this subject I can find on the forms and still have some questions.

Let me set this up this way:

I have a 1949 Deluxe Touring sedan with a 288 engine in it. The fuel pump is a dual style that was rebuilt by Max Merritt. The carburetor is the Carter WDO-type which was professionally rebuilt locally. My gas tank has been professionally cleaned inside and out and has been coated with the proper type of chemical sealant/liner. My problems with keeping the engine fed with fuel have been solved, with one exception:

When it sits for a day or two, or if it's extremely hot, if it doesn't start immediately, it is unfair to try to get it to. I do not like to crank it over and over again, so I end up pulling the breather off the carburetor, pouring a little bit of fuel in the car, and starting it that way. Then it runs just fine.

Based on the advice of many, I added an electric fuel pump made by the Holley Corporation back near the fuel tank. The holy technical service man recommended their Mighty Mite Fuel Pump, and their technical support expert assured me that it did not hinder fuel from flowing through it when it was turned off. It is a 12 volt DC unit, so I ran a dedicated pair from a 6 to 12 volt converter I installed under the dash directly to the 12-volt inputs of the fuel pump. I installed a momentary push button switch that completes the circuit to the input of the converter, and I use it to activate the pump when I need it.

However, even after all of this, I'm having the same issue. No matter how long I let the pump run, it doesn't seem to help the carburetor and the fuel system to go ahead and allow the car to start. I have verified that the flow of the electric pump is correct, it's not wired in reverse, and there's nothing blocking the hoses. Once I get it running, it runs just fine, but I just can't get it to start using the priming pump.

My question is this:

Is it possible that the electric fuel pump is functioning as a "check valve" on the fuel supply line as it arrives from the electric pump? In other words, is the mechanical pump preventing the freshly pressurized fuel in the fuel line from making it to the carburetor? Would I be better off allowing the electric one to run for a given time before I started up?

Posted on: Today 14:36

Todd W. White
Sapulpa, Okla.
1949 2262 DeLuxe Eight Touring Sedan

humanpotatohybrid

Re: Electric Fuel Pump (again, with a twist)

Home away from home

Mechanical fuel pumps work through a double-check-valve spring-diaphragm system so just a slight fuel pressure should be enough to flow through both check valves and fill the carb.

How long do you leave it on? Might need to be 10 sec or more.

Posted on: Today 14:41

Todd W. White

Re: Electric Fuel Pump (again, with a twist)

Quite a regular

I've tried various times, nothing more than about 15-20 seconds, for fear of damaging the mechanical pump, even though the Holley pump is rated at 4-7 psi output pressure.

Posted on: Today 14:46

Todd W. White
Sapulpa, Okla.
1949 2262 DeLuxe Eight Touring Sedan

Ross

Re: Electric Fuel Pump (again, with a twist)

Home away from home

Unhook your fuel line at the carburetor, hold it over a can, and see if the electric pump pumps through.

Posted on: Today 15:11

Todd W. White

Re: Electric Fuel Pump (again, with a twist)

Quite a regular

That's my next step - thanks for the encouragement!

Posted on: Today 15:14

Todd W. White
Sapulpa, Okla.
1949 2262 DeLuxe Eight Touring Sedan

HH56

Re: Electric Fuel Pump (again, with a twist)

Forum Ambassador

If you have the optional glass bowl filter next to the carb you could also check and see how long it takes to fill that bowl. Modern gasoline -- at least the stuff sold here in Calif -- appears to be more volatile compared to the older 50s fuel. After you park the car the fuel sitting over a hot manifold tends to bubble or percolate away fairly quickly leaving an empty carb. In my cars sometimes the electric pump needs to run for several minutes to fill the tubing between the pump and filter and then fill the filter and carb float bowls. I usually keep it on while starting the engine and then after the engine is running and stable turn it off.

Posted on: Today 15:28

Howard

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