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Old 08-30-2004, 05:55 PM
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DuaneS DuaneS is offline
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Boat: 1998 200 VRS Maristar, 5.7 EFI Vortec
Location: Florida
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annoying power loss

I have a 1998 200 Maristar with the 5.7 TBI. Lately the engine stalls when pulling a skier out of the water. I have found that when it happens and I stop and put the engine in neutral and rev to around 3000 rpm after 30 seconds or so the engine "clears its throat" and you can hear the rpm get smooth again. I've changed both filters several times this summer but it comes back after a couple hours operation. The nearest authorized shop is 4 hours away so I really need help from you pros.
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Old 08-30-2004, 06:34 PM
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Boat: MasterCraft PS205 351 HO
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Duane


You say changing “filters” helps out for a few hrs.. Did you look for water in the gas tank? Just a thought

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Old 08-30-2004, 06:35 PM
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Oh,

And welcome aboard....
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  #4  
Old 08-30-2004, 08:59 PM
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Any time you have a problem like this, look at the fuel system. Next, clean your flame arrestor. Carb cleaner works fine for this. I happen to like the NAPA cleaner that evaporates really fast.

Take a fuel sample and check the pressure. The easiest way I have found to take a sample is by using a fuel pressure gauge with a purge valve, pressing the button and letting some gas go into a clean, clear bottle. If you have a timing light, verify spark on all cylinders. If you have run out of gas more than once, your pump may have problems since the gas actually cools the impeller in the pump.

If you do a search for fuel related problems here or at the old site, you'll see a lot of people talking about the screen at the inlet of the pump. Remove the line from the tank after turning the anti-siphon valve closed(look at this first, just in case it turned a bit and is restricting the fuel flow from the tank). If you have a hose crimping tool, put that on the fuel line so the gas doesn't run into the bilge. There is a fitting on the pump where the screen is. You may find it easier to remove the pump to remove this. Most likely, there is some garbage in the screen. Get this out of the way and it should run great again.
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Old 08-31-2004, 10:14 AM
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Like Jim said check you fuel system first. If it continues to have issues I would look at the ignition system.

How many hours on your boat?
Has the SES light come on during one of these episodes?

The ignition system the TBI uses is notorious for having problems. The distributor shaft magnetic pickup loses its ability to send a signal to the module and it cuts out like you are describing. It is compounded when the engine is under load. Also a no load rev of the engine has been known to somehow "excite" or repolarize the pickup on the shaft to temporaraly fix the issue.

It is a headache to diagnose because in most cases it will not trip the SES or set a code until complete failure. Also the only way to fix it is rebuild the distributor shaft or replace the entire unit. If your boat has a lot of hours it is probably getting close anyway. Also I have seen many boats that have very few hours and are not run on a regular basis that need a distributor rebuild. I think the lack of use causes the shaft to loose its polarity faster than a boat that is used on a regular basis.

Hope it helps and good luck................
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Old 08-31-2004, 02:52 PM
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Deisel- you mean notorious for problems in boats, or generally?

I wasn't aware of a code or indication for a distributor malfunction. On the other hand, the waveform from the pickup coil could be looked at on a 'scope to see if it's adequate. The pickup coil senses the gaps in the pole piece when they pass the coil and send a voltage spike to the IC module. The IC module then sends a square wave to the ECM to tell it the RPM. Also, the pickup coil isn't dealing with enough current to produce a high strength magnetic field in order to remagnetize the pole piece.

I still think it's fuel related, but not having seen the boat and not knowing the service history, it's hard to guess. How old are the cap and rotor, plugs and wires? Do the fuel pressure test and take a sample, then look at the other things.
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  #7  
Old 08-31-2004, 03:19 PM
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Quote:
Originally Posted by JimN
Deisel- you mean notorious for problems in boats, or generally?
Generally, boat or truck.

I cannot tell you how many of these shafts I have replaced over the years. When I had my shop I kept a couple on the shelf ready to go. Some would last forever some would go at 40K .

I am sure you have seen this with your 90 model truck with 200K+.

Quote:
I wasn't aware of a code or indication for a distributor malfunction.
This was my point. Without a code the problem is very hard to diagnose. IIRC once it would not run anymore it would usually trip a 42 or 43 DTC code identifying the ignition system as the source. It's been a while since I replaced one though (retired)
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Old 08-31-2004, 03:25 PM
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What was the actual symptom on the trucks? Idle OK, then start getting lumpy, rev it up a bit and problem goes away? Mine does this occasionally, but there's never a problem with accceleration.

I would chalk it up to having a permanent magnet on a steel shaft, immersed in a magnetic field with a shield around it. Sounds like a recipe for eventual failure to me.
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  #9  
Old 08-31-2004, 03:40 PM
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Quote:
Originally Posted by JimN
What was the actual symptom on the trucks? Idle OK, then start getting lumpy, rev it up a bit and problem goes away? Mine does this occasionally, but there's never a problem with accceleration.

I would chalk it up to having a permanent magnet on a steel shaft, immersed in a magnetic field with a shield around it. Sounds like a recipe for eventual failure to me.
Actually most people misdiagnosed as drivetrain. Going along the highway and it begins to mis or cut out like the trany was slipping. That was usually how the truck ended up in my shop; we specialized in drivetrain.

This usually occured in OD converter locked with a load (up hill usually). Most the time they idled fine and accelerated fairly well unless they were towing or in a low rpm load as described above.

Today most mechanics can't or won't do anything unless the scanner tells them the exact problem.
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Old 08-31-2004, 05:21 PM
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Tell me if I'm wrong, it happens in OD, no load other than what's in the bed(not very much) at about 37 MPH? I thought it was bad to tow in OD.
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