Electric fuel pump operation

[sailmaster]

Hello,
I am installing a second racor filter in line with a 10 micron element.I need to bleed the system.According to what I read,you turn the ignition key on and let the electric fuel lift pump run for 2-3 minutes to purge the air.I could never hear the pump[click,click] running.The pump will not operate with the ignition key on.After 2 hours of checking connections etc.etc.I discovered it operates only when the pre-heat button is engaged.In order to bleed the system I cannot imagine your suppose to hold the preheat button for 2-3 minutes.Do any other members have this or is this normal.Any suggestions or fixes.
Thanks

[Oswego John]

The pump will not operate with the ignition key on.

I discovered it operates only when the pre-heat button is engaged.In order to bleed the system I cannot imagine your suppose to hold the preheat button for 2-3 minutes.

Hi Richard

From what I read, it seems that the "Ignition" switch feeds the preheater push button, which in turn feeds both the preheater(s) and the fuel pump. This doesn't sound right.

I would think that the push button has only one function, to feed electrical power to the preheater(s) and to have no effect toward the fuel pump.

When the engine is running, whether motoring or idling, my guess is that you don't have to keep the preheater button depressed constantly to supply power to the fuel pump. There is most likely another route for electrical power to reach the fuel pump.

Do you have an electrical schematic plan for your engine ?

Good luck,
O J

[Klem]

It depends on what engine you have and how the ignition is wired (I am assuming that you do in fact have an electric fuel pump). Quite often, the fuel pump won't turn on until the starter has been engaged. In this scenario, you turn the ignition to start for a second then leave it on and you should hear the pump.

If you can give more details on what your setup is, we can try to be more specific.

[Steve Laume]

What Klem says makes sense of your situation.

The panel on Raven was wired so that the key supplied power to the preheat, then it jumped from there to the starter button. If the pump only runs after the started has seen power, then that would explain why you have to depress the preheat button before the pump will run.

I had always found it very annoying to have to hold two buttons in at the same time to start the engine. It seemed there were all sorts of reasons not to power things that way. Extra draw while turning the starter, more connections and a switch to possibly cause problems while starting.

I powered the preheat and starter buttons independently from the key. Now I can press the preheat for the required amount of time or not at all then release it and hit the starter button.

Life is simple with this arrangement and would let you prime your engine simply by turning the key.

If anyone sees a potential problem with this arrangement I would be interested in hearing about it, Steve.

[sailmaster]

It depends on what engine you have and how the ignition is wired (I am assuming that you do in fact have an electric fuel pump). Quite often, the fuel pump won't turn on until the starter has been engaged. In this scenario, you turn the ignition to start for a second then leave it on and you should hear the pump.

If you can give more details on what your setup is, we can try to be more specific.

Thanks, after installing a secondary racor I need to bleed the system,The westerbeke brochure says'just turn on ignition key and let my electric pump run for 2-3 minutes to purge the air and then start the engine.That makes sense however my electric fuel pump operates when the pre-heat button is depressed not when the ignition key is turned on.

[Steve Laume]

Ya know, it sounds like somebody connected the fuel pump wire to the wrong side of the preheater button.

whoops, then it wouldn't pump fuel once you stared the engine.

Weird problem, Steve.

[Maine Sail]

On some engines I have found the pre-heat button will engage the fuel pump, also kills the alarm buzzer, and then once the engine is running, with the oil pressure switch made, the fuel pump will also work. This is a safety cut out so if you lose oil pressure the fuel pump will cut out.

Simply use an alligator jumper lead from the +solenoid to the POS term of the fuel pump to activate the fuel pump when bleeding it.

Follow your schematic and you may find your fuel pump is part of the alarm circuit and won't run until you have oil pressure. No spinning engine and oil pressure no fuel pump..

[sailmaster]

On some engines I have found the pre-heat button will engage the fuel pump, also kills the alarm buzzer, and then once the engine is running, with the oil pressure switch made, the fuel pump will also work. This is a safety cut out so if you lose oil pressure the fuel pump will cut out.

Simply use an alligator jumper lead from the +solenoid to the POS term of the fuel pump to activate the fuel pump when bleeding it.

Follow your schematic and you may find your fuel pump is part of the alarm circuit and won't run until you have oil pressure. No spinning engine and oil pressure no fuel pump..

Thanks for your imput,I think the aligator clip idea after any major interuption regarding the fuel system is probably the easy fix until I can figure it out.
By the way ,your website is well done and very helpful with lots of pics and info.Thanks again.
Richard