mounting of an in line electric pump

Discussions related to electrical and fuel system, gasoline, etc.
Post Reply
dak955
Posts: 133
Joined: Mon Jan 26, 2015 6:10 pm
Location: Medina, Ohio

mounting of an in line electric pump

Post by dak955 » Mon Sep 11, 2017 1:23 pm

I am having a fuel delivery issue on a 1939 120.....it has a freshly rebuilt carb and rebuilt fuel pump.it has an in line electric fuel pump (similar to an airtex E8902) mounted at the tank with a clear plastic filter between the tank and electric pump. For whatever reason, the electric pump is mounted at an angle (about 30 degrees) with the output higher than the input. The engine runs for a couple of minutes then dies out, being out of gas at the carb. When this happens, there is no gas visible inside the fuel filter at the tank. No gas in the carb when I pump it. If I let it sit for 30 minutes or so, gas has re-filled the fuel filter...I then turn on the electric pump for a few seconds(it has a separate toggle switch) , turn it off and start the car. Runs for a couple of minutes and dies out. All fuel lines have been blown out and the fuel filter is new. The electric pump was new when I recently got the car. I am going to start isolating things to narrow down the issue. I just wondered if anyone had some ideas and I also wondered if the electric pump being mounted at an angle could be an issue. Thanks.

Howard56
Posts: 1125
Joined: Mon Dec 24, 2012 11:35 am

Re: mounting of an in line electric pump

Post by Howard56 » Mon Sep 11, 2017 2:46 pm

When you say similar to an E8902 I assume that means it is not an Airtex pump. Airtex doesn't mention any restrictions on position but if yours is a different brand I wouldn't think it would have restrictions either but --------. One other question would be whether the pump you have will allow the mechanical pump to pull sufficient fuel flow thru when it is off. The Airtex is a solenoid type and will allow flow thru but not all pumps are the same. Most rotaries for example, will not allow fuel to pass or if they do, will severely restrict flow if they are not running. That could also be the case with some non rotaries.

There was another poster with a rotary pump that was having fuel delivery issues when using only the mechanical pump. Placing a check valve in parallel with the pump seems to have taken care of his problem and if nothing else comes to light I would wonder if that might be worth trying with yours. viewtopic.php?f=8&t=4511&start=10#p21644

While it seems unlikely one other thing worth checking is the gas cap. That has caught some having delivery issues because an original gas cap was replaced with a non vented cap or, for some reason the vent hole was plugged up.

Adam
Posts: 1064
Joined: Fri Sep 04, 2009 4:15 am
Location: lincolnshire, uk

Re: mounting of an in line electric pump

Post by Adam » Tue Sep 12, 2017 2:34 am

Do you need the electric pump? In any case, why not try eliminating that from the system and see what happens? Just join the flexibles together and give it a try.

As Howard described, if you retain the electric pump for priming purposes, it should probably be connected in tandem with a by-pass pipe, controlled by a one-way valve. That way, the electric pump should work for priming, but not offer any resistance to the mechanical pump when the engine is running.

Adam..
"Do not underestimate the English cousin.....they are not as stupid as they look!" - Signor Altabani in The Italian Job.

dak955
Posts: 133
Joined: Mon Jan 26, 2015 6:10 pm
Location: Medina, Ohio

Re: mounting of an in line electric pump

Post by dak955 » Wed Sep 13, 2017 5:36 pm

Thank you Howard and Adam for your responses. As an update, I have narrowed down the problem to either the pick up in the tank or thr rubber line between the tank and the inlet of the electric fuel pump. I connected a line from the inlet of the electric pump and put tge other end directly into a can of gas and it ran great for 20 minutes or so. No stalling or running out of gas. Re-started it after a few minute shut down and it started right up. Thanks again.

Post Reply