02 EFI 175 Alarm and power limiting??

[fig-fixs-it]

Hello all...first post as you can see. Did a search and didn't seem to find anything but I don't know all of the correct vernacular either so...here we go.

The motor has 189 hours, impeller was replaced maybe two years ago as the overheat alarm was coming on, sounding that code.

As stated I've got a '02 EFI (NOT optimax) motor and I started having an issue that started last year, the last time the boat was used. The issue was that once, for less than a second, the alarm sounded when at WFO (not a code, just a steady BEEP) and power was limited. Once the alarm went off, like I said, less than a second, power was back on and all was good.

Fast forward to this year...hooked the engine up to a hose, ran it prior to a trip down to Louisiana. Ran fine...get to Louisiana and the engine was running pretty well but the alarm did sound a time or two, but only at WFO and after we'd been on-plane for a bit. Meaning if I put it to full throttle the alarm would not come on until the boat had planed out and we'd been running WFO for a little bit. Also, it seemed that if running around 3,000-3,500 rpm, on-plane the alarm would not go off.

Last day of this trip to Louisiana, 6am and we clear the no-wake area (salt water running) and I put it to full throttle, we get on-plane and after a short time, maybe 2 minutes tops, the alarm goes off, still just a solid tone (which I have nightmares about...I hate the alarm), and power is limited, the engine stalls and I'm met with a transom wash-over from the sudden loss of power taking the boat quickly from 50MPH-zero. We decide to fish as best as we can with the trolling motor and let the big motor "cool". I did not think it was an overheat issue, as no code was being beeped, did not know what it was, just that there was some sort of problem.

I proceed to take the hood off, and disconnect the water separating filter sensor (guessing at what it might be), then the on-engine oil tank's low oil level sensor. After letting the motor cool of big time, the alarm is still going off. And it goes off now as soon as the motor is started. Anyway, sorry long boring tale, we finally get back to port. Once there, I put the boat on the trailer, the alarm has now stopped going off. I load the motor while on the trailer...still no alarm. As it's that last day of the trip we decide not to risk it and put the boat away.

Last week I install a new Smartcraft Monitor gauge and put the boat into some a smooth body of water, a canal, and run it. I run it wide open for almost an hour. Watching water psi mostly and RPM. Water pressure seems a little low but I don't know what it should be?

• Water pressure is around 3 psi at idle, in-gear
• Water pressure is around 15 psi when running WFO

I'm quite perplexed as to what it could be. From what I read, a solid tone from the Smartcraft system is sort of a wildcard of some kinda issue, who knows what. But from my experience things don't just "fix themselves."

And sorry to sound super cheap, but it does not feel like a good value to got to the dealer, have them hook up to my motor, pull a code and charge me $120 for a few minutes of work (and yes I know the scan tool is spendy but c'mon). I've been thinking about buying a used scan tool from eBay or Craigslist...I've seen them out there for $500-$800. And hell, if the dealer is going to charge me $120 to pull a code, why not just pony up and get my own scan tool right? If they do it four times I'm already almost to $500!

Thanks for reading...hope it makes sense, and thanks for any input!

 

[CharlieB]

Re: 02 EFI 175 Alarm and power limiting??

First and most important expense is to order a FACTORY Service Manual for your motor. The Merc manual will have all the diagnostics necessary for determining your current problem and any future problems you may have.

With that said, the difference in running between cruising speed and WOT is fuel flow, WOT requires much more fuel and produces a lot more heat. ANY small restriction in the fuel supply will cause the motor to run lean which radically increases heat. The alarm and power reduction by the ECU is an attempt to prevent major piston/cyl damage from happening.

Water pressures are not unreasonable.

Fuel flow is critical. Inspect the fuel system, beginning with the fuel tank dip tube and the valve within the tank fitting for any foreign matter that may restrict flow.

Disconnect the fuel line between the pulse pump and the VST, point it into a suitable container, pull the lanyard and crank the motor to observe the fuel stream to ensure you have a strong pulsed flow.

Connect a fuel pressure gauge to the high pressure fuel line at the fitting provided and monitor the fuel pressure while under way, the pressure should remain steady at all throttle settings.

Remove the temp sensors and Ohm's test while heating in a pan of water, observe for a marked change in value near 180 degrees.

Remove the water separating filter and pour it into a suitable container, looking to see how much water has accumulated.

Any one or a combination of these can trigger an alarm

 

[fig-fixs-it]

Re: 02 EFI 175 Alarm and power limiting??

First and most important expense is to order a FACTORY Service Manual for your motor. The Merc manual will have all the diagnostics necessary for determining your current problem and any future problems you may have.

I could not agree more...I'll be ordering one tomorrow.

With that said, the difference in running between cruising speed and WOT is fuel flow, WOT requires much more fuel and produces a lot more heat. ANY small restriction in the fuel supply will cause the motor to run lean which radically increases heat. The alarm and power reduction by the ECU is an attempt to prevent major piston/cyl damage from happening.

I get the idea of the alarm system...and I hoped that it was due to a overheat issue, but I also question whether or not it would be so sensitive as to detect lean-running. And, I've had the alarm come on for overheat in the past, and it would beep a code BUT not limit power. This time is was limiting power. I let the motor "cool" for at least an hour (hood off) after the alarm came on. As soon as the motor was started at idle the alarm was still going off, still just a solid tone, and limiting power even at idle. It was as if once the Smartcraft system detected whatever tripped it, it was stuck in this power-limiting "safe" mode.

Given all this, I'd have to guess, and rule out an overheating issue.

Water pressures are not unreasonable.

Fuel flow is critical. Inspect the fuel system, beginning with the fuel tank dip tube and the valve within the tank fitting for any foreign matter that may restrict flow.

Disconnect the fuel line between the pulse pump and the VST, point it into a suitable container, pull the lanyard and crank the motor to observe the fuel stream to ensure you have a strong pulsed flow.

Connect a fuel pressure gauge to the high pressure fuel line at the fitting provided and monitor the fuel pressure while under way, the pressure should remain steady at all throttle settings.

Remove the temp sensors and Ohm's test while heating in a pan of water, observe for a marked change in value near 180 degrees.

Remove the water separating filter and pour it into a suitable container, looking to see how much water has accumulated.

Any one or a combination of these can trigger an alarm

Thanks, it all sounds like good advice. I guess my confusion is that I've had the alarm sound in the past. for the water separating filter, and for overheat. And both times they sounded a code. This time however, no code, just a solid tone and then the motor went into it's protection mode. If the motor was running hot I'd expect to have heard the beep code for o-heat. And if for water in the water separating filter I'd have heard that code as well. Not too mention that after letting it cool off, the alarm should have stopped at this point right? Motor is now relatively speaking, cool.

Thanks again for the help Charlie. If you or anyone has any insight into the solid tone thing that would be great. And as I've said, it has since run fine while @ WFO since the issue happened bad (which was in April), and for a solid hour. Which has me further confused. I just don't think the issue has fixed itself but the motor is now behaving perfectly.

Which does not mean on my next trip out, when offshore, that it won't quit and leave me floating with at the whim of the prevailing winds. All this just leaves me less than confident in this motor.

 

[CharlieB]

Re: 02 EFI 175 Alarm and power limiting??

How old is the boat/fuel tank?

Do you pre-mix any fuel?

Could there be a small piece of a foil cap adrift within the tank?

I (and others) have found foreign matter stuck on the fuel pick up tube, a piece of debris would suck up against the tube, held by the suction of the fuel tank.

Once the motor died and fuel suction died, the piece would drift away and all was well again, until the next time.

These are the types of problems that are real P.I.T.A. to find.

 

[fig-fixs-it]

Re: 02 EFI 175 Alarm and power limiting??

As an aside to this thread...does anyone know if the FSM allows diagnostics to be done WITHOUT the scan tool? A lot of Toyota products for example will let you short a wire and get flash code. I was thinking maybe Mercury did the same thing with their beep codes somehow?

Or said another way, can you get very far into diagnosis without the scan tool? Or for certain issues is it a must-have item to figure things out?

 

[raymor]

Re: 02 EFI 175 Alarm and power limiting??

Do a scan for trouble codes using a test light. I saw it on there one time and all you have to do is plug the trouble light into the harness.

 

[fig-fixs-it]

Re: 02 EFI 175 Alarm and power limiting??

How old is the boat/fuel tank?

Do you pre-mix any fuel?

Could there be a small piece of a foil cap adrift within the tank?

I (and others) have found foreign matter stuck on the fuel pick up tube, a piece of debris would suck up against the tube, held by the suction of the fuel tank.

Once the motor died and fuel suction died, the piece would drift away and all was well again, until the next time.

These are the types of problems that are real P.I.T.A. to find.

Just ordered the manual...guy at the boat shop said diagnostics really cannot be done without the DDT.

Anyway, premix, no...boat and motor are '02. I don't really thing this could be a fuel flow issue as there is no loss of power. Boat runs great until the computer decides that it needs to be shut down. I like the thought process though about the foil. But unfortunately I don't think that's it.

The running issue was pretty consistent. Again, the issue really only happend once last year...and if I didn't lay it out it went like this:

Boat being ran WFO across a like, alarm goes off, steady tone, no flash code, lasts for less than half a second, cuts power at the same time. After it stopped, it was fine, and for the rest of that day it was also fine.

 

[fig-fixs-it]

Re: 02 EFI 175 Alarm and power limiting??

Do a scan for trouble codes using a test light. I saw it on there one time and all you have to do is plug the trouble light into the harness.

Looks like no unless I missed something:

http://forums.iboats.com/showthread.php?t=284110&highlight=test+light+code