The Stovebolt Site Forums The Shop Area The Electrical Bay Electric fuel pump

I added an electric fuel pump as a priming pump. the one I install is suppose to work as a stand alone pump or can be used as a priming pump. I wired it with a spring loaded push button so in only runs when I manually push the button. the reason for the pump is that after my truck sits for a while the fuel drains out of the line and it take a lot of cranking until the fuel line is charged again. After that, the truck runs fine and will start right up until it has sit for a couple days.

Here is the issue. I have the pump installed about 2 feet from the gas tank. This particular pump works better pushing fuel so it was suggested to have it close to the tank. I push the button and can hear the pump going the town. Problem is, I don't see any fuel being pushed into the clear fuel filter that sits right in front of my carburetor. I still have to manually prime the carburetor with a squirt of gas from a bottle. I wouldn't think so but if I have it wired backwards could it be running in reverse and trying to push gas toward the gas tank? I know my heater fan motor reverses direction when I reverse the polarity. I can easily reverse the wiring to test it but I was not sure if that would possibly damage the pump if I wired it with the polarity reversed.

Did you test the pump prior to installing it? I'd suggest removing the pump and see if it works, or maybe just pull the gas line upstream of the mechanical pump and see if it will fill a catch can when you push the button. Permanent magnet motors reverse direction with a polarity change- - - -ones with field coil windings don't.
Jerry

Not sure what gets accopmplished with adding a electric pump to a mechanical pump. It's the carb bowl that is evaporating. I would think the gas would stay at the mechanical pump. There is a finger over the straw situation there.

If the electric pump is wired correctly then you have proven it's doing no good. I hope you are pumping pedal as starter turns and full choke.... on these after "sitting a long time" days. You need to get a squirt as soon as there is enough in the bowl.
I think maybe you may start to suspect a bad accelerator pump.

If filter is "right in front of the carburetor" does that mean after the mechanical fuel pump? That is the wrong place. Put it before pump.

I have an electric priming pump on EVERYTHING including fork lift, lawnmower, and diesel air compressor. Zero start problems or run down batteries.

I have NEVER used an electric pump on a mechanical pump motor and have zero start problems and no run down batteries with a good pump, starter and battery..
I have had other no start issues. There can be other reasons for his hard start. He could be using a bandaid on the wrong sore.

Carb, weak mechanical pump, cold weather morning..............starting technique.

A little more information. I have a fresh rebuild of the carburetor by a guy who has been doing it for over 50 years. I have a brand new mechanical pump (Carter). If I pump the gas pedal and crank it long enough it will eventually get gas into the carburetor and start. Being a 6v system the brand new 6v battery does not like to crank and crank the engine. It is a race to see if it starts before I drain the battery. Yes, I have a fuel filter between the fuel pump and the carburetor. I have seen this set up on countless vehicles. I am not sure how this is impacting things. The glass bowl on my mechanical fuel pump stays full of gas. The fuel level in the filter in front of the carburetor is very low after a couple days. I was expecting to see fuel pump into the filter with the electric fuel pump running. That would make it readily available to pump fuel into the carburetor with just a couple pumps of the accelerator. I will pull the output connection and run the pump to see if it is pushing fuel. I have another pump I can try if it is not.

Sounds like a bad electric pump. I've got nothing against an inline electric pump between the main mechanical pump and the tank. I do this too when I don't have a gravity assist to the main fuel pump. If you pull the line from the mechanical pump and connect the inline pump to the battery you should start squirting fuel. If it doesn't than you've got a bad inline pump or it's not wired the right way. Only thing I'd caution is that there are some inline pumps that don't let fuel pass when they're off. So make sure you have one that'll allow fuel to bypass, you really don't need those inline pumps when the mechanical one is primed.

This specific pump is advertised and compatible as a stand alone or as an inline assist. It is suppose to allow the mechanical pump to take over once it is turned off.

Is it one of the small bullet style pumps? Looks like D cell battery with nipples on it?

If so, both of the ones I used died pretty quickly. They would make noise like they were running, but no fuel came out.

Visible fuel filters are the scourge of the earth. A pump test is what is needed ASAP. thru all filters.

Yes, the D cell battery looking pump. I will be testing pump shortly.

Every vehicle I own runs and starts on a mechanical pump with no help from electric pumps.

If your mechanical pump isn't getting the job done, it probably needs a rebuild. As bartamos said, pump the hell out of the carburetor while you're cranking the engine. Maybe your accelerator pump is weak.

What's the story on your mechanical pump? New? Original? Rebuilt recently? If it's a new pump, get rid of it and find a good used original pump to rebuild.

Not sure how those fuel filters with a glass bowl before the carb are to be installed but I ran in to a situation once where I just turned the filter upside down (bowl on top) and finally got fuel to the carb. It's been running this way for a few years now. Worth a try.

I've used a low pressure electric pump since 1997 with excellent results. In fact I replaced it about 7 years ago with another just like it...not becase it wasn't working but because it had been in use for so long. In my opinion, it has been better than any mechanical pump I ever owned and ethanol doesn't bother it a bit. Even if the truck has been sitting for two or three weeks without being started, it takes no time at all to fill the float bowl and start. Model is Autobest 4027 and output is 2.5psi to 4 psi...just what you need for the 235. Mine outputs 2.7 psi. You can buy one for less than $25 last time I looked.