HELP!!!!!!! Severe loss of power on my 2002 350 MAG MPI-gctid390524

[Guest]

WOW what a bummer. We recently purchased an 02 2855, and had a great 200 mile run home from Lake Union to Comox B.C. The boat preformed beautifully the entire trip. We spent two weeks cleaning and detailing, and we've had nothing but trouble ever since.

Here's the symptoms:

starts and idles fine

won't come up over about 2500 rpm

won't get up on plane

no throttle response after about 1/4 throttle

smell of un burned fuel in the exhaust

runs a little rough and shudders a bit over idle

Here's what i've tried:

changed rotor, cap, plugs, wires, coil, fuel filter. No change.

Suspected bad gas so tried fresh fuel from another source.....no change

Here's what I think... I suspect a ghost in the machine!!!!

Either the ECU ( or computer) or one of the many sensors or the wiring harness

Has anyone had similar problems, any help would be greatfully appreciated.

thanks in advance

Chris

[Guest]

I had similar problems- great idle, no performance at anything over 2000 rpm- and traced the problem to a 2nd inline fuel filter that was totally clogged. Trace your fuel line from the tank to the engine and look for an old school GM style metal canister filter inline. On my 2359, it was buried way under the deck.

Hopefully that is the problem.

[Guest]

Thanks, Pete

I have only found 1 fuel filter, it is the can type that looks like an oil filter no, others in line.

By the smell of fuel when it is running I suspect it is getting fuel but not burning it. Although the engine fires up ok, it shudders from time to time while it is idling, it doesn't sppear to be running on all cylinders' and it does not come up above about 150 degrees.

I'll try to locate a merc mechanic today, wish me luck!!!

Thanks for your opinion, any and all suggestions welcome

Chris

[Guest]

My 5.7 Mag is doing the same thing but without the smell of fuel. It had worked great until new fuel was added. I replaced the fuel separator and did find water mixed in with the fuel but still have the same problem. I have also pulled the in line fuel filter and it does not appear to be plugged as I am able to blow air through it. I am planning on changing the in line filter today. Will a GM automotive filter fit it and if so can anyone tell me what to cross reference it with?

[Guest]

I'm not sure about an automotive filter, I would stick with the marine version. I have only found the one filter/water seperator. Where on your 5.7 did you find the in line filter you referred to??

On my engine the fuel line comes from the tank to a canister type filter on the starboard side of the engine, then to the "cool fuel" unit on the port side and from there to the injectors. I have yet to find another filter.

Chris

[Guest]

I have the same setup but there is an in line filter just above the fuel tank. It looks identical to an automotive filter

[TenMile]

Wally wrote:
WOW what a bummer. We recently purchased an 02 2855, and had a great 200 mile run home from Lake Union to Comox B.C. The boat preformed beautifully the entire trip. We spent two weeks cleaning and detailing, and we've had nothing but trouble ever since.

Here's the symptoms:

starts and idles fine

won't come up over about 2500 rpm

won't get up on plane

no throttle response after about 1/4 throttle

smell of un burned fuel in the exhaust

runs a little rough and shudders a bit over idle

Here's what i've tried:

changed rotor, cap, plugs, wires, coil, fuel filter. No change.

Suspected bad gas so tried fresh fuel from another source.....no change

Here's what I think... I suspect a ghost in the machine!!!!

Either the ECU ( or computer) or one of the many sensors or the wiring harness

Has anyone had similar problems, any help would be greatfully appreciated.

thanks in advance

Chris

Sounds like the engine is going into Engine Guardian mode. When you turn the key on, do you hear the engine alarm test tone (long solid beep) before you start? I had an issue with my last boat where my engine alarm wasn't connected properly so it didn't beep when in Guardian Mode. The symptoms you describe sound just like it -- boat starts and runs but won't throttle up, hesitates etc... but you should hear the engine alarm beeping.

Check all your gauges, oil, voltage, temp etc and be sure everything is 100%. A failed alternator will cause it to go into Guardian mode as will Over Temp, Low Oil and a bunch of other things that can damage the engine. You can reset the ECU by disconnecting the battery for a few minutes. Your local Merc mechanic can attach the diagnostic tool to get any codes off the ECU -- a Mercmonitor will also present you with those codes if your engine is supported.

[Guest]

Thanks for the tips,

Seems I swapped a couple of the distributor leads when changing them.....OMG

Took a mechanic and 170 bucks to find out.

HOWEVER... I still don't seem to have the preformance I should.

It takes a fairly long time to get up on plane, and once there I have to keep the throttle wide open, surely this is not normal, or am I expecting too much??

I just don't seem to have the power I should.

As far as the alarm goes it sounds two beeps when the key is turned on.

Any other ideas??

By the way, what is a Mercmonitor???

[CaptTom]

Not sure what you're expecting. This isn't a race boat, but it should plane smartly when:

- Only one or two people on board

- bottom is clean

- No excessive gear or baggage on board

- Tanks half full

- prop in perfect condition

Each of these things can contribute a little to the loss of performance and difficulty getting on plane.

You did a long trip on it, presumably you had luggage and various tank levels. Is it worse now than it was on the trip? If so, did you hit anything? Even a soft grounding in mud will ding your prop enough to reduce performance. Only after eliminating all that would I look at engine issues.

[Guest]

Thanks Cap'n Tom

Yes I definately think the performance has tanked since out trip home.

We didn't hit anything and the props are A-OK

I have poor batteries, and wonder if they may contribute to the problem, so will replace them next.

I am abandoning this thread for the one entitled "02 2858 350 MPI saga continues"

See you there

Chris