6v Fuel Pump with Mechanical Pump.

[Phil Gillespie]

Prior to taking 38 PU for a 6 monthly WOF checked out and see fuel coming from diaphragm cover at mechanical fuel pump. 8BA engine is also fitted with inline electric fuel pump under vehicle.
Discharge pressure from mechanical pump with electric pump is 3.5psi.
Disconnected electric pump pump and engine ran for a bit then stopped.
Confirms electric pump is not a flow through pump when not running.
Checked fuel pump, pushrod ok and fitted in place. Diaphragm ok and not damaged. This leakage occurred at initial start up. Tried later and was ok.
next day similar thats why i checked it all out thinking to put in a switch to just use electric pump at start up. But my type of pump will not allow this. So a repalcement electric pump required?
Tightened down the diaphragm cover as thought should be able to hold the 3.5 psi ok. Thoughts appeciated.
Phil NZ

[Flathead Fever]

It must be fuel pump question week. This is a real common question. Sounds like you already have it figured out. If your just going to use the electric pump to prime the engine you need an electric pump that is "open" when it is tuned off so the mechanical pump can pull fuel through it. Hook it up to a push button switch so you will look cool priming your engine. You just need to make sure you get one that does not have too much pressure. Hopefully Somebody here has the Napa number for the perfect pump.

The diaphragm might have dried out and shrunk and then came back to life once it soaked in fuel. You can snug up the screws but if you tighten them too much you might split the diaphragm.

[Phil Gillespie]

Originally Posted by Flathead Fever

It must be fuel pump question week. This is a real common question. Sounds like you already have it figured out. If your just going to use the electric pump to prime the engine you need an electric pump that is "open" when it is tuned off so the mechanical pump can pull fuel through it. Hook it up to a push button switch so you will look cool priming your engine. You just need to make sure you get one that does not have too much pressure. Hopefully Somebody here has the Napa number for the perfect pump.

The diaphragm might have dried out and shrunk and then came back to life once it soaked in fuel. You can snug up the screws but if you tighten them too much you might split the diaphragm.

Yes thats what i need an open pump at off position which i can just turn on for prime only. Only this one has the electric fuel pump. Other 2 vehicles have only mechanical pumps and work well. Just to now make this one more user friendly as dont want the electric one running all the time with a mechanical pump.
The 3.5 psi is on the border for too much pressure for the Stromberg 97?
Phil NZ

[51 MERC-CT]

This is the pass-thru fuel pump (Airtex E8902) that has been used successfully by many.

https://www.ebay.com/itm/6-VOLT-ELEC...S!-1:rk:4:pf:0

[Phil Gillespie]

Originally Posted by 51 MERC-CT

This is the pass-thru fuel pump (Airtex E8902) that has been used successfully by many.

https://www.ebay.com/itm/6-VOLT-ELEC...S!-1:rk:4:pf:0

Thanks for that this should do the trick.
Phil NZ

[Pat/Ohio]

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The Airtex E8902 is the correct pump, however you can purchase it for much less. Been trending at around $30-$35 on Amazon. At least it was the last time I researched it. Good luck, Pat

[Flathead Fever]

Originally Posted by Pat/Ohio

The Airtex E8902 is the correct pump, however you can purchase it for much less. Been trending at around $30-$35 on Amazon. At least it was the last time I researched it. Good luck, Pat

Airtex pumps are very good pumps. In Verizon's fleet that was all we used during the 30-year's I was there. We used their water pumps too. They lasted just as long as the originals did. They are the best of what's available without buying OEM. In fact I have two of their in-tank pumps in my personal cars right now. One of the originals only went 60K miles. The Airtex has now gone 80K miles. Stay away from almost "any" parts that come from behind the counter of the big chain parts store. Especially anything electrical unless you know for sure that is a reliable brand. Those places are only good for buying chemicals. With one exception and that is Napa. I've always had good luck with Napa parts but then they closed the one in my town, because they sold quality parts that cost a little more nobody was going there. The customers were all going up the road where they could get a lifetime guarantee and it cost less. That's not going to mean much when your in the middle of Death Valley in July and your bargain fuel pump takes a crap.


The one problem with "external" electrical fuel pumps is they do "not" tend to last as long as the modern in-tank fuel pumps That is because they run hotter than the in tank pumps do, which are kept by the fuel. They all will eventually fail. You can usually tap on them with the key on and they will come to life including in-tank pumps if you kick the crap out of the bottom of the tank. That will get you home. You usually only get a couple of those taps before it quits completely.

Airtex also makes original style mechanical fuel pumps for flatheads and water pumps.

Lately I've been ordering stuff from Rock Auto. You just need to check if Amazon or Rock Auto is the cheapest. If you have a newer Ford try to always get Motorcraft parts. If you have a Chevy use Delco parts when you can get them online. They are usually too expensive to purchase from the dealer unless your desperate.

[Phil Gillespie]

Originally Posted by Pat/Ohio

The Airtex E8902 is the correct pump, however you can purchase it for much less. Been trending at around $30-$35 on Amazon. At least it was the last time I researched it. Good luck, Pat

Checked and went with Rock Auto at $32.00 they also offer the best shipping rates which are significantly better than other suppliers.
Appreciate advice.
Phil NZ

[FireEngineMike]

Charlie ny makes diaphragms that last, even if you use ethanol.

[JMFL36]

I am thinking of adding a flow-thru inline fuel pump to my stock positive ground 6V 1934 Phaeton for priming purposes only. I was planning to wire power to the pump thru an ignition switch activated fuse panel port, and the pump ground to an old single-wire Ford starter switch button mounted under the dash. How does that sound?

[JSeery]

The fuel pump (and any other accessery) needs to be connected using a relay. The original ignition switch was not designed for higher than the original current flow.

[Mike in AZ]

From what I understand, you want fuel pressure to be 2-2.5 psi. Mike

[JM 35 Sedan]

I wouldn't connect fuel pump to ignition switch. I would connect it direct to hot side of line but thru a separate fuse and use momentary contact switch. I see no need for a relay.

[JSeery]

Relays are always a good idea, BUT they are a later technology. Direct wiring will work as long as it's not through the ignition switch.

[Phil Gillespie]

Originally Posted by JSeery

Relays are always a good idea, BUT they are a later technology. Direct wiring will work as long as it's not through the ignition switch.

Have the relay for the job and a 6v pump which can be used for priming as required, and able to be" pulled through" by mechanical pump when not in use. Present 6v pump not able to do this. Other cars work well for me with nil electric fuel pumps. Just so happens this one already had the electric pump fitted. Always better ways to do things and the input and suggestions on this site are great.
Phil NZ

[Tinker]

What's wrong with a mechanical pump?

[Phil Gillespie]

Originally Posted by Tinker

What's wrong with a mechanical pump?

Nothing wrong with a mechanical pump in my experience.
Phil NZ

[Graeme / New Zealand]

Phil check out Fuel flo electric fuel pumps. NZ made i've got the 6v one. Good unit and just use it for priming, attach a universal inline fuel filter to it..one of those glass jobs

http://www.fuelflow.co.nz/FF_cms_03/...&product_id=70

GB