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groefsema17

Replace fuel pump? 03 Monsoon 335 Malibu VLX

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groefsema17

Hi all

I have an 03 VLX with the 335 Monsoon in it. Its been having a bug lately. Started the end of last season, I winterized motor, added fuel with Stabil and put her to bed. Woke her up with a fake a lake, and had the same issue. Its basically dying after running for about 10 minutes. Gauges are all good. No beeping when it dies. It dies just like if I had turned the key to off. The next couple cranks it will start up, but eventually won't start at all until I let it sit for 30 min or more. After reading multiple posts and learning, I cleaned IAC, TPS, and pulled fuel pump and cleaned the intake screen. Also changed oil, oil filter, fuel filter and impeller. Started boat again, and no issue yet. However, my fuel pump is still kinda whining. So I rented a fuel pressure gauge and it reads 36-38 lbs at all RPM's. Reading on here, that is about the minimum I should have. Volts to fuel pump is 13.4-13.8. Should I be expecting the fuel pump to take a big stinky on me soon? Or anything else I should check before spending $300? I did check the kill switch as well. It dies when I pull the lanyard, and gauges come back to life when I put lanyard back. I have already ordered new distributor cap and rotor, as well as spark plug wires, because I'm sure they are still the originals. (fyi, bought boat last year from the original owner) Thanks in advance.

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tvano

no good ideas but if it's your boat in your avitar i love the look

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vigwilson

My guess is all the pumps read a little differently. I could almost put money on the filter. I had a 99 that did the exact same thing as yours and got stranded on the water. I went through the fuel system from sending unit to fuel rail tapping on every component with the wood handle of a hammer. It fired right up and never had one problem again. My guess is it got a little gunked up and broke free. Run some lucas cleaner through it for a few tanks. Or sea foam

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groefsema17

Thanks guys. Ya, thats our boat in the picture. For now, Im gonna hope that the distributor cap, rotor and spark plugs come in soon and do the trick. Will get it on the water soon hopefully with no issues. Unless There are any other ideas. Thanks again crew

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Steeli

Hello, you can check the fuel pressure at the connector at one rail, before you change the pump. I had a similar problem last year, problems ocour after 30 minutes. I changend sparks, plugs, cap, rotor and fuel filter. At last ignitopn coil was the problem when hot..

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electricjohn

Problems after warm up are usually electrical and centered around the distributor and coil. Take a good look down in your distributor at the pick up region. A common trouble spot on '03s

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groefsema17

Thanks Electric. I replaced the distributor cap, rotor and spark plug wires tonight. Ran outta time to actually run it and check it out. But there was quite a bit of rust buildup under the rotor on the post. I took a rag with electrical cleaner and cleaned it up as much as possible. I would have to believe that this build up is a culprit. Hopefully I dont have to replace the coil! The 03s are known for bad coils? Or what exactly? Thanks again

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Pnwrider

Thanks Electric. I replaced the distributor cap, rotor and spark plug wires tonight. Ran outta time to actually run it and check it out. But there was quite a bit of rust buildup under the rotor on the post. I took a rag with electrical cleaner and cleaned it up as much as possible. I would have to believe that this build up is a culprit. Hopefully I dont have to replace the coil! The 03s are known for bad coils? Or what exactly? Thanks again

I saw quite a bit of buildup/corrosion when I replaced the cap/rotor on my 03. That was at roughly the 450 hour mark.

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electricjohn

Look for corrosion or build up down inside the distributor by the pick up wheel.

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groefsema17

There was a little corrosion, but not much. However, I did change the distributor cap, rotor and wires anyways. Problem is still going on....Today I ran it at an idle for 5, checked out. 2000 rpm for about 3 min, check. 3000 rpm for about 15 seconds, then died, as if I had turned the key off. No sputter or anything. Gauges looked ok, temp wasn't even to 160 yet. I'm debating on replacing kill switch, even though I think it is functioning. i.e. gauges die when I pull it, regenerate when I reinstall. The IAC did have a lot of carbon build up on it when I cleaned it initially. Could this be killing the motor all of a sudden? Please help!!!! Thanks crew.

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justgary

Unless the gauges died with the engine, it's not the kill switch. IAC is not really in play at 3000 RPM, so that is probably not it either.

This sounds like something that is getting hot and quitting. Did you do the fuel pressure test when it died? With injectors, the pressure only has to drop for a moment.

Have you pulled the cannon plug and checked the connections?

Right now, my money (well, more like your money) is on the coil. Possibly a bad pickup or capacitor in the distributor.

You have to definitively figure out if it is fuel or spark...

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groefsema17

I never got it to die when I had the fuel pressure gauge on it. Go figure! But will get ahold of the gauge and do it again.

I did pull the cannon plug. All connections look good.

I'm guessing its a bad coil too.... damn it.

Thanks

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Steeli

My Problems with the defect coil ocour after 30minutes over 2800-3000rpm! My Dealer gave me on coil for testing. Mercruiser use the same parts.

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groefsema17

Final verdict - I went through everything once again from the start. 2 spark plug wires were crossed and I changed the coil. Like new! Ran it for 5 hours on The Delta, and ran like a charm. Hope this helps....

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