engine looses power

[bigairnut]

big problems...03 Wakesetter VLX...boat runs great but after running for 30 mins or so it starts looses power to the point where it won't pull wakeboarder/skier out of water. If I turn boat off then back on it seems to have power for a few mins but then looses it again. It comes and goes. The longer I run it when the power is gone, the worse it gets. Sounds like it has backfired a few times also. I have replaced the plugs. Fuel was treated before winter. I have topped off with high test gas and STP water treatment. Now I have boat tied to dock and running to burn off the rest of the gas so I can try brand new gas. Early in the day it has full power and feels good but then it starts dying and has no pull at all and won't top out. Any help would be greatly appreciated. Thanks in advance.

[electricjohn]

When was the last time you changed your fuel filter?

[bigairnut]

changed the fuel filter the summer before last.

[UWSkier]

How's your voltage when this happens? Reason I ask is cause a voltage drain coming in somewhere can rob the fuel pump of needed juice.

[bigairnut]

i believe voltage is fine but not certain. the voltage gauge is unresponsive. most of them are though. the oil pressure gauge works sometimes and not at others. the temp gauge is the same. i am assuming this is a separate issue as it has been this way for a few years but i have been too lazy to fix them. i assume this problem is the MMDC or something.

[skier92]

Fuel filter would be pretty inexpensive to eliminate by replacing. Next start looking at grounds and wiring connections. Iv'e had four wiring connections that eventually just broke where ther wire enters the terminal end.

[Pappy]

Same thing started happening to me. Does the engine sound like it is flooding? Here are some things I have checked: replaced fuel filter, rotor, cap; spark plugs look good (light brown) and are all even; getting good voltage to the fuel pump. It feels like a fuel issue to me but the fact that we can turn it off and on and it goes away for a while makes me think the ECM resets whatever it is that is causing it. I will try to check the TPS and see if it changes anything. If you find anything let me know.

[bigairnut]

sorry to hear you are having the same trouble but glad someone else is working on a solution also. when the engine looses power it does feel/sound as if the engine is flooding - i give it some throttle and it just muffles and drops power like crazy. it gets worse if i keep trying or if i just cruise at the same speed. if i stop and key it off then restart it is fine for a few minutes then does the same thing again. there have been a few loud "thud" sounds also - don't know if this is a hard engine knock or what. i plan on calling indmar and/or malibu today to inquire. will let you know what they say.

[Sandbagger]

Sounds to me like the engine is starved for fuel. I would replace the fuel filter and see what happens.

[mlange]

I'd swap out the fuel filter and also make sure the vent line isn't plugged up.

Mike

[notoutenough]

Mine had what sounds like the same thing also last year. I changed the fuel filter and cap and rotor and it's been running great since.

BTW, when I took off the cap and rotor, the leads were really corroded, which seemed like the majority of the cause.

--Robert

[bigairnut]

I talked to Indmar today. Tech said it could be a faulty fuel pump. He said when we turn the key off and then back on it may be resetting the pump so that is why it is working initially when restarted. He said to check the pressure of the fuel system. He said there was a place to hook up a pressure gauge but it is raining here so I don't feel like uncovering the boat to see if I can find it. Any one have any suggestions where this hook up will be, what it looks like and where I can get a fuel pressure gauge? Tech said it should be around 40 psi. I would need to hook up the gauge and drive the boat until the problem occurs again then check the pressure. If it has dropped significantly he said it is the pump. Is the pump in the tank or outside and easily reachable?

Thanks to all who are replying.

[Ross Calvert]

I had the same problem on my Sunsetter LXI and it was the fuel filters. Ther are two, one on the motor and the other at the fuel tank. The one near the fuel tank has steel mesh inside. If there any moisture in the tank it may collect in the filter and rust up the interior. I change both every season now. Plus I use a octane booster/fuel additive like Sea Foam. You can get it at Walmart. The additive has alcahol in it that binds with the water and allows the engine to burn it. Havnt had a problem since

[99response]

I had the same problem on my Sunsetter LXI and it was the fuel filters. Ther are two, one on the motor and the other at the fuel tank. The one near the fuel tank has steel mesh inside. If there any moisture in the tank it may collect in the filter and rust up the interior. I change both every season now. Plus I use a octane booster/fuel additive like Sea Foam. You can get it at Walmart. The additive has alcahol in it that binds with the water and allows the engine to burn it. Havnt had a problem since

There will only be one in line fuel filter on the OPs 03 VLX.

To the OP - change the fuel filter first, a plugged up filter could cause the issues you describe. Also, its best to start changing a $8 part before you go ahead and change out the $400 pump.

[Sandbagger]

Check this and maybe will shed some light on what you are trying to accomplish: http://www.2carpros.com/dia/test_fuel_pressure.htm

Could be the fuel filter, pump or pressure regulator. I would always replace the filter first as that is the easiest and cheapest fix and often the culprit.

[bigairnut]

thanks for the link. nice info. i will look into this more this weekend and let you all know.

[aaudii5150]

How's your voltage when this happens? Reason I ask is cause a voltage drain coming in somewhere can rob the fuel pump of needed juice.

We had this issue last weekend. We smoked the alternator and LOW voltage and reduced power...... It's real easy to check

the voltage from the alternator. Just touch the hot lead to the orange wire and ground the other. You should at least 13.5 volts.

Good luck

[Pappy]

So I went ahead and tried to troubleshoot today. Got a pressure gauge and hooked it up (in my motor Chevy 5.7 the test hook-up point is on the rail on the side opposite the alternator/plastic cap covers it) the pressure read at 36psi with elec power on. I turned it on and stayed at 36psi while running at idle. I unhooked the regulator and it went up 8psi. So far so good. I took the boat out and it still misfired and while it misfired there was no significant change in psi. Note when running the pressure was closer to 40psi. When it finally started bogging down the pressure was dropping to 20psi. So based on the video mentioned above I thought it was the pump. When I got home I called Indmar and the tech said he did not think it was the pump and asked me to pinch the return line. I pinched it and the pressure jumped to over 100psi. He said that if the pressure rose the pump was probably good enough to keep up with the fuel demand and thought it was probably the regulator. BTW-He mentioned the correct fuel pressure should be between 36-44psi. I guess his reasoning is the regulator could fail open. I did not get a chance to play with the return line while the boat was in the water hopefully I can do that later and see it the pressure rises as I clamp the return line down.

Of note replaced the TPS no luck and put on my spare ICM and it did nothing. I tried to see if the tip about the alternator by turning the batteries off and the boat ran fine for the most part but died twice near idle. It never died before with the batteries on. The voltage jumped around a little but nothing I would call definite. I think I would have known about a bad alternator as soon as I turned the batteries off. ???

I am running out of ideas I don't want to change the regulator or pump without more concrete evidence. Any help is appreciated.

[XTI04]

I have seen ignition modules do this. The vehicle runs great until the module heats up then it looses power or has a bad miss. Auto parts stores use to be able to test them, but the accuracy was marginal at best.

[fastjohnny]

Have you dried out your distributor?

I have read a theory about engines loosing power after heating up, and vaporizing trapped water under the distributor cap that accumulates due to condensation.

The other possibility is as the engine is heating up, something is drawing increased resistance. It could be possibly informative by using an ammeter to determine amp draw with engine cold and hot.

[Pappy]

Did some more testing and here is what I found. I went ahead and clamped the fuel return line while the motor was running until the pressure rose up to about 60 psi. the engine ran well without missing or bogging down for a while. After about 10 min it began bogging down and the fuel pressure went down to about 25psi. While it was doing this I went ahead and completely clamped the return line and the pressure did not rise above 25psi. Went I brought the throttle back to idle the pressure would only rise to 40psi. I am thinking it's a bad fuel pump but would like some thoughts before ordering a $350 part. I did not check the voltage to the pump while this was happening to see if I have 12v+ I think this would be the last thing I have to check. It could be me but I though the pump was very noisy. Does anyone have the same noise problem with their pump?

Thanks

[XTI04]

With those numbers it looks like you are back to a fuel problem. If the filters are new and there are no kinks or other restrictions on the inlet side of the filter then it is time for a pump.

[Pappy]

Problem solved!!!! I called Indmar yesterday and the tech rep told me that a whining fuel pump was a sign that the pump was not getting enough fuel to work properly. He told me to undo all the fittings all the way back to the fuel tank and to check if there was any debris. I did not find anything in the tank or in the hoses but there is a small filter inside the inlet to the fuel pump that I would have never seen had I not taken the fuel pump out. It looks like a sprinkler head screen filter but about 1/2 in long. Well it was filthy. I went ahead and cleaned it put everything back together and put it in the water. BTW the pump primed on its own in about 10 secs. The boat ran better that it has in a long long time. I am so happy. In the end all it cost me was the price on my new fuel pressure gauge. Hope it helps bigair nut.

[bigairnut]

Congrats Pappy! I have not had time to check mine. I bought a new fuel filter and a fuel pressure test gauge the other day but it has been raining most afternoons. I hope to attack it today or tomorrow. I haven't looked around too much - is the fuel pump in the tank or outside? Thanks.

[Pappy]

Congrats Pappy! I have not had time to check mine. I bought a new fuel filter and a fuel pressure test gauge the other day but it has been raining most afternoons. I hope to attack it today or tomorrow. I haven't looked around too much - is the fuel pump in the tank or outside? Thanks.

On my motor it is outside. It is a silver soda can looking cylinder on the right side of the motor.