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Fuel Pump Issues


Umatilla Matt

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I'm having fuel pump issues on my 1997 Sunsetter LX.

The fuel pump just stops working intermittently. I've experienced this problem twice now, which has been the last two times I've been out on the lake.

The first time I thought I was vapor locked at first, but then noticed the fuel pump wasn't priming when the key was turned. I looked over everything, checked connections, and tapped on the fuel pump. Eventually had to be towed in. Hooked the boat to the fake-a-lake when I got home and everything worked fine. Fuel pump primed and all was well. Checked the wiring again for a loose connection and couldn't find anything.

The second time this happened I was pulling a wakeboarder and the boat just started losing power and eventually stalled. Once again the fuel pump wouldn't prime. Wiggled all the connections and still nothing. After waiting about 10 minutes, I tried turning the key again and this time the fuel pump primed like normal. Got the boat almost back to the dock and it stalled again. Tried to start it back up and once again the fuel pump wouldn't prime. Once again waited a few minutes, this time without touching a thing, and the fuel pump primed and the boat ran like normal and I was able to get it on the trailer.

Could this be a sensor or something? It doesn't seem to be a loose connection since the pump doesn't prime even after wiggling things. I'm also wondering if it could be the pump itself. It has always made a sort of whining noise when the boat is running since I bought the boat last summer. Nothing too loud, just enough to be noticeable. I don't know what a normal fuel pump sounds like to compare. The fuel filters were replaced when I purchased the boat, but I haven't had a chance to check them yet. Would a clogged fuel filter keep the fuel pump from priming anyways?

If anyone has any suggestions or ideas I'd really appreciate some help!

Thanks!

Edited by Umatilla Matt
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How many hours on since your new fuel filter? Replace fuel filter every 50 hours. Your fuel pump should never whine. It is starving for fuel. You can ruin the pump very quickly.

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How many hours on since your new fuel filter? Replace fuel filter every 50 hours. Your fuel pump should never whine. It is starving for fuel. You can ruin the pump very quickly.

Not sure exactly how many hours since the fuel filter change. I know it was changed when I got the boat last summer and the pump had a slight whine then too. Would a clogged filter cause the pump not to prime?

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Not sure exactly how many hours since the fuel filter change. I know it was changed when I got the boat last summer and the pump had a slight whine then too. Would a clogged filter cause the pump not to prime?

One bad tank of gas can clog a fuel filter. You had better find out what is going on before you run your boat. Some people have found the screen under the pump to have problems, but I checked mine and it was clean after 10 years.

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One bad tank of gas can clog a fuel filter. You had better find out what is going on before you run your boat. Some people have found the screen under the pump to have problems, but I checked mine and it was clean after 10 years.

I'm definitely going to check out the filters when I get time, but I don't see how a clogged filter can keep the fuel pump from priming, and that is my main problem.

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I'm definitely going to check out the filters when I get time, but I don't see how a clogged filter can keep the fuel pump from priming, and that is my main problem.

Look the word "CLOG" up in the dictionary.

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Look the word "CLOG" up in the dictionary.

Ok smartass. The pump doesn't even try to do anything when its not working. Like its not getting power or something.

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EFI or Carbed engine?

If its EFI I'd check your kill switch and the fuel pump relay. You could also run the pump via jumper cables to see if it works, or just put a test light on the pump leads.

-Chris

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EFI or Carbed engine?

If its EFI I'd check your kill switch and the fuel pump relay. You could also run the pump via jumper cables to see if it works, or just put a test light on the pump leads.

-Chris

Its an EFI. One of my first thoughts was to check the kill switch, but messing with it didn't help. I don't know where the fuel pump relay is. I wish I would have had an electrical tester to check and see if the pump is getting power during its little episodes of not working.

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That's really the way to go, I'd bench test the fuel pump and put a test light on the lead when the boat acts up.

I think its electrical, the pump will make some noise even if its not pulling fuel.

EDIT relays are my the ECM above the transmission

Edited by 99response
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That's really the way to go, I'd bench test the fuel pump and put a test light on the lead when the boat acts up.

I think its electrical, the pump will make some noise even if its not pulling fuel.

EDIT relays are my the ECM above the transmission

Yeah, maybe I'll take the fuel pump off and hook it up on the bench just to verify its working. With everything that is going on I'm thinking electrical too. I'll have to see if I can find the relays. I could probably just trace the leads off the pump and make sure nothing is loose or corroded.

And thank you for confirming the pump will make some noise even if its not getting any fuel! This is something eyepeeler doesn't seem to understand :Tease3:

I'm also wondering if there are any sensors that control the fuel pump. Maybe a temp sensor or something? It just seems weird that after letting the boat sit for a while it somehow works again.

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My boat was doing the same thing. Turns out there was, what looked like, a plug with a waterproof cap on it down on the right side of the transmission. Under that cap are 3 15amp fuses, check and make sure all of those are good and there is no corrosion on them. Then check your relay, they are located under a metal panel that is mounted on the back of the motor above the transmission. Just play "musical relays" and test each one. Good Luck man. All these locations are assuming that your boat is a direct drive.

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Ok thanks! I checked the fuse labeled fuel pump under the metal cover, but I didn't know about the one on the side. I'll check it out. I'll check the relays too. They're fairly cheap to replace if it comes to it. I know it has to be something electrical, it's just going to be hard to pinpoint. Thanks for your help!

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When the boat shut down on you,did spit and sputter?Kinda like it was idling down?My boat has been doing this to me,just put a new fuel pump and filters on it.After running on the water for a short time I encounter these issues.Still trying to remedy my probs.

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Have you replaced the plastic clip on the kill switch. Sometimes the plastic will fatigue and stretch out so that it intermittently will turnoff the fuel pump. It is not much more expensive to replace the whole unit.

It took me about half a season to figure that out. :biggrin: :biggrin:

http://www.skidim.com/prodinfo.asp?number=SIEMP40970

Edited by Murphy8166
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When the boat shut down on you,did spit and sputter?Kinda like it was idling down?My boat has been doing this to me,just put a new fuel pump and filters on it.After running on the water for a short time I encounter these issues.Still trying to remedy my probs.

No, the boat will just "die" and then it won't even sputter when trying to crank it. My fuel pump is shutting off completely so the engine is not getting fuel, therefore no sputter.

Have you replaced the plastic clip on the kill switch. Sometimes the plastic will fatigue and stretch out so that it intermittently will turnoff the fuel pump. It is not much more expensive to replace the whole unit.

It took me about half a season to figure that out. :biggrin: :biggrin:

http://www.skidim.com/prodinfo.asp?number=SIEMP40970

I have now completely bypassed the kill switch and I had the same problem again when I took the boat out today. I've also replaced both fuel filters, cleaned the electrical connections on the plug to the fuel pump, and checked the fuel pump fuse.

I'm thinking what is going on has to be electrical. The fuel pump just acts like it is not getting power. I have no idea what to check next. The pump almost always starts working again after it sits for a while, even without me touching anything.

Any ideas???

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I'm gonna try to do that today, but I don't know exactly where the relays are or what they look like. And I hate the fact that there's no way to test it other than going out wakeboarding for a couple hours and see if it happens or not.

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Right next to the ECM, three in a row, black boxes maybe an 1" on each side.

My link

Thanks man, I'll take a look today. I wonder if there's anyway to test the relay in the shop instead of switching it and waiting to see if something else malfunctions.

Edited by Umatilla Matt
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You can test them but the procedure is detailed, someone may have the info on hand but I'd have to check a shop manual.

-Chris

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Ok, I've found the relays. They were on the underside of the metal plate that all the electrical stuff is mounted to.

I only have two of the 1"x1" black box looking relays. The third thing in the row is a flat maybe 3"x3" box with a plug on it. Maybe a newer type of relay?

So of the two 1"x1" relays I'm pretty sure I have the one for the fuel pump. It has a tan wire and a brown wire with a white stripe running into it and the fuel pump has the same colored wires running out of it. The other 1"x1" relay has purple wires, which I think is ignition or starter. If I'm wrong let me know.

My next question is will THIS work? Its only $10.90 instead of $69.99. It looks like the same thing, maybe just not brand name. If it will work I'll just order it and replace the old one. If not, I'm gonna have to test the old one to make sure its bad before I get a new one for $69.99.

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I'd switch the two relays around then if your boat doesn't start (the other one is ignition) or turn over you know what's wrong.

-Chris

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I'd switch the two relays around then if your boat doesn't start (the other one is ignition) or turn over you know what's wrong.

-Chris

Ok, so I located the relays. Took out the one for the fuel pump and the boat acts the same as it does on the lake when it acts up. Put the relay back in and still no power to the fuel pump. Switched the relays and everything worked fine. Switched them back to their original positions and everything still worked. Still, I'm 90% sure it has to be the one relay. It's an intermittent issue, so that would explain why it worked when I switched it back. I'm gonna try to pick up one tomorrow at an auto parts store and then I'll see what happens when I take it out on the lake.

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Ok, so I located the relays. Took out the one for the fuel pump and the boat acts the same as it does on the lake when it acts up. Put the relay back in and still no power to the fuel pump. Switched the relays and everything worked fine. Switched them back to their original positions and everything still worked. Still, I'm 90% sure it has to be the one relay. It's an intermittent issue, so that would explain why it worked when I switched it back. I'm gonna try to pick up one tomorrow at an auto parts store and then I'll see what happens when I take it out on the lake.

And what were the results? Was it a bad relay?

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