Fuel Pump Whining

[rkilcoyne]

Getting my new "used" Nautique ready for the water. This boat has a 1995 GT-40 MFI engine. When I turn the key to the on position, I hear a whining sound for about 10 secs from the fuel pump. I'm assuming that's the low-pressure fuel pump priming. To give you an idea of how loud the whine is, I can certainly hear it when the engine cover is closed.

My question is: Is that whining normal, or does it indicate there's a problem with the pump? If you have the same engine, do you hear that whining sound when you turn the key? When the boat starts it idles well, but after a minute or so, it starts to sound starved for fuel -- as if someone is pumping the throttle until it eventually stalls. Oh and you do hear the pump whining the whole time the engine is running.

I suppose the other possibility is old/bad fuel... but that whining sound leads me to believe something else is going on.

Thanks,
Rick

[charlesml3]

Completely normal. In fact, if you DIDN'T hear that sound something would be wrong. I got so used to it on my 99 Air that I would intentionally listen for it when I turned the ignition on.

-Charles

[rkilcoyne]

Here’s a brief video of starting the engine with fuel pressure gauge attached to the fuel rail. Starts at 30psi and drops as RPMs go up. Also, how about that whirring sound? Cant be right.

https://youtu.be/zd13cKndtbo

[charlesml3]

Here’s a brief video of starting the engine with fuel pressure gauge attached to the fuel rail. Starts at 30psi and drops as RPMs go up. Also, how about that whirring sound? Cant be right.

https://youtu.be/zd13cKndtbo

What do you mean by "can't be right?" It's in the video you posted. Starts at the 3 second mark.

[rkilcoyne]

The sound he fuel pump is making, and the fact that when giving the boat throttle it drops and bogs down the a stall.

[Infinity]

Have you checked fuel lines? Is it possible they are collapsing due to age and contributing to starving engine

[Blamey]

That does not sound right to me and you likely have a problem with your low pressure pump but it could also be several other issues including.

- high pressure pump
- bad relay
- anti siphon valve
- bad ecm

You could take a flier on alow pressure pump and just get a new one. Or you can test the flow rate of your current pump by attaching it to a gas container.

I have a new never used Low pressure pump which I bought last year when I was having issue, turned out to be battery related. It's for the GT40 with FCC so not sure it will work on yours.

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[rkilcoyne]

Thank Blamey -- really hoping it's not a bad ecm... I'm debating going with the LPP or just going full-bore with the FCC retro kit. Bad relay and anti-siphon valve components seem like a cheap check

[Blamey]

Also I believe that some lpp's have a screen in them, check the screen to make sure it isn't clogged.

I doubt it's the ecm. Lots more common issues to check.

Relays and anti-siphon are cheap. Always good to have spare relays.

Read the 'poor man's GT40 diagnostic' thread over on CorrectCraftFan.

Maybe even lost there, those guys are good at diagnosing engine issue.

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[Skidave]

Low pressure pumps fail frequently. Replace it and put an inline filter just before the low pressure pump.

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[kylem03]

Before you replace anything pump wise, replace your fuel filter located between the gas tank and the low pressure pump. When I bought my ‘95 last year it had a persistent whine meaning the pump was starving for fuel. Similarly boggy on the mid-top end. Classic fuel starvation. The whine is happening because these pumps of that vintage (the high pressure pumps anyways) are lubricated by fuel. No fuel=no lube=fuel starvation= eventual pump failure. I replaced my filter 40 hours ago and no issues since.

Kyle

[rkilcoyne]

Thanks Kyle — seems like an easy place to start

[rkilcoyne]

kylem03 : Do you happen to know which inline filter you used?

[kylem03]

https://www.nautiqueparts.com/produc...-pcm-r080024a/ this one but I bought a Napa equivalent. I will try and find a Napa number.

[kylem03]

https://www.napaonline.com/en/p/FIL3482