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I posted this q in my rebuild forum... but thought would get a better response with a new topic. Have scoured the sight but don't see what I'm needing.

Post:
Ok. The original fuel pump is rebuilt and installed. I currently have a 6 volt electric pump installed and have a few questions about the whole hook up...

1. I would like to keep the elec pump on for a primer pump. So the question is, will the AC pump pull fuel through the elec pump or do I need to put in a bypass and valve system to accommodate the elect pump on a switch.

2. Does anyone out there have the fuel line/vacuum line diagram on hand... (Jim L.) So I can get the fuel and vacuum lines back to original configuration.

The inlet valve or connection looks to be a larger size and thread than the out side of the fuel pump. So a few connections and fuel lines are in order... advance auto and napa are getting to know me WAY to well....

any advice and coaching is welcome...

Hopefully someone will get back to you on the vacuum line photos. I don't have any showing complete routing. As to the electric pump -- it depends on which electric pump you are using.

Typically the pulse types work similarly to the mechanical types with a diaphragm or some sort of piston arrangement. Those have valves which will allow you to pull fluid thru like the valve arrangement on the vacuum side of the mechanical fuel pump allows air to pass. Many of us have that type in use and do exactly as you want to do.

Rotary types usually will not let fluid pass since their output depends on the spinning motion -- pull it in from one side of the rotors, spin it around a closed cavity and eject it from the other side. If you are using that type it will need a check valve and bypass arrangement.

I have an electric inline fuel pump in my 38 and the manual pump draws through with no problem.

Except for the now nearly obsolete rotary type electric fuel pumps, mechanical fuel pumps will draw thru an electric pump. The thing to remember is that if it causes any restriction at all it will result in the mechanical pump working harder, thus lowering the pressure in the line preceeding the mechanical pump, thus more prone to vapor lock- though in practice this may not be significant. Fuel under pressure is more resistant to vapor lock than fuel under suction so it's a great idea to mount the electric pump as close to the source (the fuel tank) as practical. My choice has always been to rely on the mechanical pump and use the electric to prime an engine that's been idle for a while, and otherwise only use it when symptoms of vapor lock appear.

ok... I took all advice and left the pump on line at the tank, and will hook a switch soon. The AC pump iw chugging right along with a few quirks...

1. The fuel filter bowl isn't filling up unless I pick up the RPMs and then only slightly. Normal?

2. The car ... "studders or Lunges" slightly at about 60 MPH. Or what the speedometer says is 60 MPH with the slight bounce...

3. Last... well last for now... She wants to stall out when coming to a stop after driving at low speeds... like through the neighborhood. I think it is starving for fuel, as in #1 where the filter bowl is not filling up.

Any fixes or suggestions?

Could be more than one reason for the bowl not filling -- but it should be full all the time.

One cause could be filter. If you have the ceramic type filter -- or any others -- after your gas tank problems would verify the element is clean again.

Just for grins if it's ceramic clean it by soaking then forcing some acetone or some other solvent and air thru backwards. I had that bowl not filling up experience and it turned out to be a varnish clogged element. It looked clean and you could blow air thru just fine but was still internally clogged to the point it would only let a limited amount of gas thru. The slow gas flow never moved fast enough for the air to completely empty out and engine was also starving for gas. If you have a later relatively inexpensive paper or fabric type I would just change it.

Believe you said you a new hose but that is another common symptom of a collapsing or old flex hose.

I will try the soaking the filter to see if this is the issue... Oh.. yes its the original filter, I've done the blow air thing, but not soaking thing... Ill try it tomorrow. its strange, because when the electric pump is in use, the bowl fills with no problem. Might be more pressure.. too much pressure at an idle.

as for the flex hoses... they are all new, and dont seem to be collapsing.. Im looking for better hoses though. I currently have standard cut to length stuff, and need some with the connections built in. I think NAPA carries them, just not sure. The original fuel lines i removed were Green. and 3 Packards in the local junk yard of the same years were also green. so im assuming this was standard...

For what its worth, the PAC website has a write up on the subject of series fuel pumps versus electric. If you have not read it, it is worth the effort.

Here is the link:http://www.packardclub.org/html/electric-fuel-pumps.htm

I used what the article calls the Seagrave method (after Seagrave Fire Apparatus, safety guidelines). This is the parallel pump method.

The electric pump I purchased includes a check valve that prevents any circular flow through it, so the mechanical pump, rebuilt a few years ago, doesn't even notice.

Pat