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Now What? Please Advise.


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2006 21 LSV with 320 LCR. Fuel pump replaced Labor Day weekend. I've put maybe 2 hrs. on the engine since then.

I "de-winterized" today. Changed distributor cap and rotor. Changed fuel filter. Hooked up battery. Dropped the boat

in the water. She cranked right up, but I could immediately hear a strange noise: a stacatto hum (sounds to me like

someone humming a Morse code message). Irregular short and longer bursts. Loud enough to hear over the idling engine.

I watched the engine gradually come up to operating temperature and hold there. I then idled out of the "No Wake" zone,

watching oil pressure, fuel, and temperature closely. I gradually ran her up to about 20 mph, continuing to watch. I then

put her through the paces (driving like I stole 'er), off and on, for about 20 minutes. No stuttering. Nothing else

even remarkable. But, when I returned to the marina and idled back to my slip, I could hear the same noise.

I'm pretty certain, after getting down low in the driver side rear storage with the dividers removed, that the noise is

coming from the fuel pump. If I hold my fingertips on the pump, I can even feel it.

Any ideas? Aside from it being annoying, is this worrisome? I don't recall hearing this when I took the boat out after

the new pump was installed, but, to be honest, I was out with my daughter and her college friends, with music playing

most of the time. Its possible that it was doing this from the get-go, but I don't really think so.

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I would call the place ie dealer parts dept and ask them I would replace it ...should not be a noise sounds like a diaphram... Not worth getting stuck in the lake..FWIW

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Noise from a fuel pump is generally caused by an air leak, or too much restriction, causing the pump to "whine". That being said, a staccato noise might also be from the anti-siphon valve on the fuel tank. With lack of use over the winter that might be sticky. Just a thought.

Peter

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Noise from a fuel pump is generally caused by an air leak, or too much restriction, causing the pump to "whine". That being said, a staccato noise might also be from the anti-siphon valve on the fuel tank. With lack of use over the winter that might be sticky. Just a thought.

Peter

So, if I were to optimistically assume that the anti-siphon valve might, in fact, be causing this, is there anything I can do to stop it?

Will it quit on its own? Spray some carburator cleaner into it? Run some Sea Foam (gas already has marine Stabil in it)? Or should I just

replace it and see if the problem goes away ($30 part, and it'll cost me at least twice that, in gas alone, to trailer it and tow it to the

dealer and back)?

Thanks.

Edited by srab
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I'm not aware of a solution short of replacing it, _IF_ it is the cause. I would start with a new fuel filter, check all the hose clamps, and check fuel pressure.

Peter

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I would call the place ie dealer parts dept and ask them I would replace it ...should not be a noise sounds like a diaphram... Not worth getting stuck in the lake..FWIW

Fuel pump was replaced in September. Only about 2 hrs of service since then, but purchased over 6 months ago with, IIRC,

a 90 day warranty. Very expensive part. I'm hoping its not the pump.

Edited by srab
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I'm not aware of a solution short of replacing it, _IF_ it is the cause. I would start with a new fuel filter, check all the hose clamps, and check fuel pressure.

Peter

Brand new fuel filter. Hose clamps tightened on either side. I guess I could re-check the clamp on the line coming into the pump

and the clamp on the hose from the anti-siphon, but I doubt either is sucking any air or I would likely have noticed the noise when

I ran the boat in September (remotely possible that I could have missed it, but I just don't believe so).

I don't have a problem replacing the anti-siphon valve, though, since its relatively inexpensive and something that I believe I can

do myself fairly easily. Are there any tricks to it?

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  • 3 weeks later...

if it starts and runs fine, don't sweat it.

Follow up: I finally made it back up to the lake yesterday. Dropped the boat in. Fired her up. Once she got up to

160 degrees, I put her back through the paces. From initial fire up, throughout the ride, and idling back to the slip,

there was no unusual noise!!! Gone!!!

I'm guessing that the air introduced to the fuel line when I changed out the fuel filter was slowly working its way

through the pump. Then, once it was all sucked through, the fuel pump quit making the noise.

However, I have changed the filter every year and never noticed this happening before.

Bottom line: if it starts and runs fine . . . .

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