Aux fuel pump (starting)

Discussions related to electrical and fuel system, gasoline, etc.
Post Reply
Zekedu
Posts: 12
Joined: Sun Nov 02, 2014 2:31 pm

Aux fuel pump (starting)

Post by Zekedu » Sun Mar 21, 2021 8:53 am

Is there a proper way to add an electric pump to prime the carb? Are there any “Gotchas” to the process?

My ‘47 custom deluxe straight eight needs help.

Howard56
Posts: 1283
Joined: Mon Dec 24, 2012 11:35 am

Re: Aux fuel pump (starting)

Post by Howard56 » Sun Mar 21, 2021 10:06 am

Most of us use a solenoid or pulse type electric pump mounted in the fuel line somewhere near the tank and controlled by a fuse and switch hidden under the dash so it can be turned on or off independently. The solenoid type electric pump will allow the mechanical pump to pull fuel thru when it is off while rotary pumps typically do not and need extra plumbing and a check valve so fuel can go around the electric pump when off. Disadvantage to the solenoid type is it is a bit noisier as compared to a rotary since you hear the clicking or pulsing motion.

The biggest "gotcha" with the electric in the line before the mechanical pump is the mechanical pump needs to be in good condition and should have decent rubber parts. The old diaphragms do not work well with todays gasoline so that should not be a problem anyway but there is the possibility an old diaphragm could split and the electric pump push fuel into the crankcase. A secondary concern is if the pressure out of the electric pump is too high it could cause carb flooding by pushing the float valve off its seat.

The Airtex E-8902 is a 6v solenoid type with 5/16 line connections. It has individual wires so can be used with pos or neg ground and has a pressure out of 2.5-4.5 psi which fairly closely matches the output pressure of the mechanical pump. If the car does not have the optional ceramic fuel filter at the carb this would be a good choice. The E-8011 at 5-8 psi is another 6v 5/16 lines choice that many have used if the car does have a filter. The extra pressure can be tolerated because by the time the fuel goes thru the mechanical pump screens and the ceramic filter element the pressure is lowered enough by the time it reaches the carb. Amazon and many parts stores are outlets for the Airtex brand pumps.

Zekedu
Posts: 12
Joined: Sun Nov 02, 2014 2:31 pm

Re: Aux fuel pump (starting)

Post by Zekedu » Sat Mar 27, 2021 6:47 am

OK! So I bought the aux pump. But when I put the leads on my 6 V battery nothing happens......not installed on the car, just pressed against the battery terminals..... thoughts?

Dave Czirr
Moderator
Posts: 5367
Joined: Tue Jun 16, 2009 5:30 am
Location: New Jersey

Re: Aux fuel pump (starting)

Post by Dave Czirr » Sat Mar 27, 2021 2:02 pm

I'd have to see the pump, but usually the body of the pump itself should be grounded (+), and only the (-) lead should be connected to the battery (-) post. If the pump you bought had two leads, possibly one is for negative ground systems and the other for positive ground systems. So best to read the instructions or wiring diagram that should have come with the pumpl.

Zekedu
Posts: 12
Joined: Sun Nov 02, 2014 2:31 pm

Re: Aux fuel pump (starting)

Post by Zekedu » Sat Mar 27, 2021 4:56 pm

The outer rim of the pump is marked “6V. OUT. +. “. It has 2 leads one black and one brown that is nearest to the “+”

No directions or info nice set of attachment pieces.

Howard56
Posts: 1283
Joined: Mon Dec 24, 2012 11:35 am

Re: Aux fuel pump (starting)

Post by Howard56 » Sun Mar 28, 2021 2:27 pm

I don't have any of the paperwork still around on pumps I have installed but have used Airtex on several cars with no issues. If you bought an Airtex, here is a bit on hookup from their website. They don't seem to offer any specific install instructions online but do give a phone number if you cannot get the pump to work and want to call their tech support.
Attachments
airtex.jpg

Zekedu
Posts: 12
Joined: Sun Nov 02, 2014 2:31 pm

Re: Aux fuel pump (starting)

Post by Zekedu » Sun Mar 28, 2021 4:45 pm

Thank you Howard......you are a good man. 👍

Post Reply