Is there a way to disable fuel pump on Generator?

[meds613]

I am installing an alternative fuel kit on my standard gas generator. Most units have gravity fed gas tanks, so switching off the petcock valve is all that's needed when using alternative fuels such as NG or LP.

My unit has a fuel pump. I'm worried that it will continue to run when my generating is operating on NG or LP. Is there a way to temporarly diable the fuel pump? I located the wiring diagram from the manual.

y unit has a fuel pump. I'm worried that it may burn out when I'm using alternative fuels, such as NG or LP.

 

[atikovi]

Pull the fuse or relay or disconnect the plug at the pump itself?

 

[oldcodger]

Post your question here:

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Guys there are really good at answering questions about generators.

 

[dnewton3]

This isn't rocket science. The schematic already shows one switch run as a relay.

Find the circuit feeding the fuel pump itself, insert a manual switch. I would put it in series after the relay.

Done.

 

[JohnnyG]

I see that's also your low oil pressure shut off. You will lose that capability.
Unless you get fancy of course, then it might approach rocket science.

 

[meds613]

This isn't rocket science. The schematic already shows one switch run as a relay.

Find the circuit feeding the fuel pump itself, insert a manual switch. I would put it in series after the relay.

Done.

I aspire to one day find these things easy to do. Can you refer me to a type of switch for this application?

 

[Nukeman7]

This isn't rocket science. The schematic already shows one switch run as a relay.

Find the ground circuit feeding exiting the fuel pump itself, insert a manual switch. I would put it in series after the relay fuel pump.

Done.

To make it as simple as possible (according to the provided wiring schematic), I'd just install a single pole, single throw [on-off] switch on the (-) ground wire exiting the fuel pump. It is the longer wire shown under the fuel pump in the lower right corner of the schematic when viewed in landscape orientation. This will allow you to keep the low oil alarm function.

A switch like this will work.

 

[JohnnyG]

To make it as simple as possible (according to the provided wiring schematic), I'd just install a single pole, single throw [on-off] switch on the (-) ground wire exiting the fuel pump. It is the longer wire shown under the fuel pump in the lower right corner of the schematic when viewed in landscape orientation. This will allow you to keep the low oil shutoff function.

Not while running on NG or LP.

 

[Nukeman7]

Not while running on NG or LP.

Correction...according to the schematic, the low oil function appears to be an audible alarm, not an automatic shutoff. Therefore, it should still be functional if the fuel pump ground wire is interrupted with an on-off switch.

 

[ekrampitzjr]

I'm curious about this. Low oil shutoff seems to be a standard feature on a lot of generators. Is significant oil consumption or loss really a huge issue in engines in this application? Other applications using similar engines seem to get by without it, and I seldom have run into low oil with small four-stroke engines in normal use. Of course, checking oil level needs to be done.

 

[oldcodger]

I think the low oil cut off is used with the thought that these engines would run unattended for hours at a time.

 

[JohnnyG]

Correction...according to the schematic, the low oil function appears to be an audible alarm, not an automatic shutoff. Therefore, it should still be functional if the fuel pump ground wire is interrupted with an on-off switch.

The way I see it, it may indeed activate an audible alarm, but it also cuts power to the fuel pump. Notice the dashed line going over to the pump switch, that the key.

 

[Nukeman7]

The way I see it, it may indeed activate an audible alarm, but it also cuts power to the fuel pump. Notice the dashed line going over to the pump switch, that the key.

You are correct, Johnny. I overlooked that circuit interruption solenoid.

 

[Fla]

Pull the fuse or relay or disconnect the plug at the pump itself?

Or unplug the relay. On many generators, the FP is driven by pulsating vacuum/pressure pulses from the engine crankcase so you would only need to unplug the rubber hose and plug it.

 

[JohnnyG]

Or unplug the relay. On many generators, the FP is driven by pulsating vacuum/pressure pulses from the engine crankcase so you would only need to unplug the rubber hose and plug it.

Thought of that too, but this one appears to be electric.

 

[Fla]

I'm curious about this. Low oil shutoff seems to be a standard feature on a lot of generators. Is significant oil consumption or loss really a huge issue in engines in this application?

Yes, it seems to be. Also the fact that people use the genereators non-stop (24/7) when the power goes off so the hours adds up a lot faster than they realize. 50 hours for example is only a bit more that two days run time. The last time that we needed a generator we lost power for 5 days. At one point (the 3rd day IIRC) the low oil detector did shut it down! Most people that use generators under those circumstances aren't very mechanically savvy to start with so the low oil shutdow probably prevents a LOT of Warranty claims against the manufacturer.