Engine alarm help

[BIGALF]

I just had a raw water pump put on my 5.7 EFI Bravo III Mercruiser. This is the second time out when I cruised at idle speed for about 2 mile then went to WOT when the alarm went on and the engine went at reduced RPM. I think the reduced RMP is a safety that is made for the engine.(I can't find it in the books anywhere) The temp gage was between 150 and 175 all the way. I thought I might have just blocked my water intake for awhile. However, I turned around to take the boat back but it ran fine at 1000-1500 rpm (no wake zone area) so I continued on my trip. Went about 5 miles at all speeds with no issue. However, right before I pulled up to the ramp I put it in neutral and reved the engine to see what would happen. The alarm went off again. I took the boat out of the water and flushed the engine and the water flowed out very strong. What is wrong? Do you think it might be the alarm itself or the tension on belts or what?

 

[alldodge]

Re: Engine alarm help

I just had a raw water pump put on my 5.7 EFI Bravo III Mercruiser. This is the second time out when I cruised at idle speed for about 2 mile then went to WOT when the alarm went on and the engine went at reduced RPM. I think the reduced RMP is a safety that is made for the engine.(I can't find it in the books anywhere) The temp gage was between 150 and 175 all the way. I thought I might have just blocked my water intake for awhile. However, I turned around to take the boat back but it ran fine at 1000-1500 rpm (no wake zone area) so I continued on my trip. Went about 5 miles at all speeds with no issue. However, right before I pulled up to the ramp I put it in neutral and reved the engine to see what would happen. The alarm went off again. I took the boat out of the water and flushed the engine and the water flowed out very strong. What is wrong? Do you think it might be the alarm itself or the tension on belts or what?

Sure could use a serial number or at least a year.

I take it this is an EFI engine. If it is a solid alarm it can only be one (From - Fun Times)

1.) engine coolant temp overheat,
2.) low engine oil pressure,
3.) engine overspeed,
4.) exhaust manifold cooling temp overheat
5.) sea pump PSI low.
Note #5 is known to be a common problem, It's been said that this fault might not show up in the fault history section of the scan tool.
If that is the case then the only other way to know if this is your problem, is to watch this sensor live as it happens out on the water with the scan tool hooked up to the engine.
Also make sure all the Battery cables are clean & tight plus a fully charged Battery is very important.
Check the water pressure sensor threads for any paint, Also check the sensor to see if it has come loose or Has a blockage of some kind.
If any sensor loses it's ground it could sound the alarm. As an additional test, try adding a ground wire to the sensor threads to stop the horn.

A constant beep is the outdrive lube level

 

[BIGALF]

Re: Engine alarm help

Thanks will try all the above.

 

[BIGALF]

Re: Engine alarm help

Sorry it's a model 45711KS 5.7EFI engine OK 022420. I had a factory rebuilt engine replacement on Jan 2007

 

[alldodge]

Re: Engine alarm help

Did you find anything from checking?

Was it a solid sound or a series of beeps?

Reving the engine high in neutral can sound the alarm if you rev it high enough.

 

[BIGALF]

Re: Engine alarm help

Will try to check it this weekend. It was a solid sound I think but I'll try it again and see what happens. Thanks for the rev issue. I never noticed that before. I didn't think I had the engine safety guard until the RPM dropped when I did the WOT and the alarm went off.
I hope it is just the raw water pump issue or a sensor.

 

[BIGALF]

Re: Engine alarm help

Ok, just came back from a test with the boat. Ran the boat for about 15 minutes to get out to a no wake zone. Then I slowly moved the speed up and the engine went on guard mode( It dropped RMP about half and the alarm went on steady beep). I stopped the engine and looked inside the hatch and saw nothing different. Checked oil and outdrive oil and all was fine. The water temp gage was a little over 150 F.
Started the engine again and ran it for another hour at all speeds and no problem. Also, before I took the boat out of water I changed the oil and saw the oil filter had oil in it so I guess that means that the oil pump is working fine.
The boat ran with the oil pressure at 39/40psi. This is what it always was for the years that I had the boat. Water temp ran from 150 to 174 max. Temp would always go down as I slowed the boat.
Any Ideas what is wrong? Could it be the incorrect temp gage was put in and or the audio warning system is not functioning correctly?

 

[thumpar]

Re: Engine alarm help

Have you had the codes read? You can make a code reader from a paperclip and an LED.

 

[BIGALF]

Re: Engine alarm help

I guess that will be my next job. I'll have to get a Mercruiser service guy to do this check. Maybe it's just an overheating sensor or something to do with the new thermostat, or the new raw water pump.

 

[thumpar]

Re: Engine alarm help

You could do this. The LED can be found at Radio Shack.

Some of you may know this trick, but I thought I would share it in hopes that it helps some folks. It is very easy to make a simple, but very useful, Marine EFI Code reading and clearing / Base Timing Tool. And you can make it for under $1.00!

Materials needed:

One 12volt resistor type LED light
One small paperclip cut in half

That’s it!

This home made code tool works every bit as well as the one I paid $50.00 for. It will work on most 1993 to 2000 marine EFI systems with the ten pin Data Link Connector. This includes Mercruiser, Volvo, Crusader, PCM, Indmar, and a few others.

How to hook it up:

1) Ignition key “OFF”

2) Remove the cap from the Data Link Connector (DLC)

3) Slide the LED into the female terminals of position E and F on the DLC, making sure that the positive side goes into terminal F and the negative side into terminal E. No damage will occur if you get it backwards, it just won't work.

4) Turn the ignition key to the “ON” position. The LED should come on steady.

5) Insert the half paperclip into terminals A and B – This puts the engine in “Service Mode” and codes will begin to flash on the LED. On 1996 and earlier engines you may hear the fuel pump come on. If not you should be able to hear the Idle Air Control (IAC) motor move. Use care in this step, do not insert in the wrong terminals or ECM damage could result! Look closely, the terminals are clearly marked.

6) Read codes by observing LED flashs. If the self diagnostic system is working it will flash code 12 – one flash, pause, two flashes, long pause – it will repeat three times. If other codes are present they will flash in order of lowest to highest. Continue to read codes until the code 12 sequence is repeated.

You can also be clear codes (by moving the throttle to 100% and back) and set base timing while in Service Mode.

 

[agallant80]

Re: Engine alarm help

Sure could use a serial number or at least a year.

I take it this is an EFI engine. If it is a solid alarm it can only be one (From - Fun Times)

1.) engine coolant temp overheat,
2.) low engine oil pressure,
3.) engine overspeed,
4.) exhaust manifold cooling temp overheat
5.) sea pump PSI low.
Note #5 is known to be a common problem, It's been said that this fault might not show up in the fault history section of the scan tool.
If that is the case then the only other way to know if this is your problem, is to watch this sensor live as it happens out on the water with the scan tool hooked up to the engine.
Also make sure all the Battery cables are clean & tight plus a fully charged Battery is very important.
Check the water pressure sensor threads for any paint, Also check the sensor to see if it has come loose or Has a blockage of some kind.
If any sensor loses it's ground it could sound the alarm. As an additional test, try adding a ground wire to the sensor threads to stop the horn.

A constant beep is the outdrive lube level

I am not sure if this helps or not but I induced number 5 before by running without a thermostat (trying to remove sand and junk from block) Too much water flow will cause the sensor to read faulty.

 

[alldodge]

Re: Engine alarm help

Ok, just came back from a test with the boat. Ran the boat for about 15 minutes to get out to a no wake zone. Then I slowly moved the speed up and the engine went on guard mode( It dropped RMP about half and the alarm went on steady beep). I stopped the engine and looked inside the hatch and saw nothing different. Checked oil and outdrive oil and all was fine. The water temp gage was a little over 150 F.
Started the engine again and ran it for another hour at all speeds and no problem. Also, before I took the boat out of water I changed the oil and saw the oil filter had oil in it so I guess that means that the oil pump is working fine.
The boat ran with the oil pressure at 39/40psi. This is what it always was for the years that I had the boat. Water temp ran from 150 to 174 max. Temp would always go down as I slowed the boat.
Any Ideas what is wrong? Could it be the incorrect temp gage was put in and or the audio warning system is not functioning correctly?

I would suggest having Merc use a scanner on your boat. The led type do not always show up the fault, there is also a posability it may not show up because it didn't stay. If you have a bad ground on the bad sensor the issue will come and go. Many time even Merc has put thread sealent on the sensors and induced a bad ground issue. Solid beeps with your engine we can add over temp and oil pressure which you have indicated they are OK, but the sensor that feeds the ECM is not the one that goes to the gauges.

 

[BIGALF]

Re: Engine alarm help

I will have the scanner used in a few weeks when the service guy gets a new one that he ordered.

 

[Fun Times]

Re: Engine alarm help

Hey guys, just a quick note about the list of things that could sound the horn in post #2. That list is for the later model engines that use the Mercruiser 555 ECM or PCM. It will not cover any of the MEFI 1-5 ECM's.

Looking at BIGALF engine serial number and parts catalog, it appears he has a MEFI 1 or 2 judging by the design of the ECM.

The older models do not use as many sensors that will sound the horn as they now have on the newer engine models.

Service Manual #17 should be the correct manual to go by for this engine model.

POWER REDUCTION MODE
(1996 AND OLDER MODELS)
The ECM will go into power reduction mode when the
following conditions are met:
1. Low oil pressure
2. Engine overheat
3. Low I/O fluid level (MCM)
4. High transmission temperature (MIE)
The ECM recognizes change of state in a discrete
switch input that identifies an abnormal condition that
may affect proper drive train operation.
As an engine protection feature, power reduction
mode allows normal fuel injection up to 2800 RPM.
Above 2800 RPM, fuel delivery is limited to half of the
injectors until RPM lowers to 1200 RPM when normal
fuel injection resumes.
This feature maintains maneuverability of the vessel
while removing the possibility of high RPM operation
until the problem is corrected.

Also have a look at this thread, Mercruiser 5,7 efi problem

 

[BIGALF]

Re: Engine alarm help

Thanks for the information. but why does the engine run fine after I turn it off and wait a few minutes and then turn it on again and run for another hour with no problem. I did this 2 different days and when I turned the engine on again it ran at all speeds and did not have any alarms or low RPMs?

 

[Fun Times]

Re: Engine alarm help

Hard to say for sure without scanning the system but really with your system the only discrete switch that would/should sound the warning horn are the oil pressure, I/O level, Transmission temp if equipped, (You don't) and engine coolant temperature.

Bear in mind that these are different switches and they would have no affect on the gauges at the dash all the while telling the ECM a different story.

First thing I would do if I did not have a scanner would be when the horn is sounding, I would disconnect each switch to see if one of them actually turned off the horn starting with the most easiest one, disconnecting both wires going to the gear lube reservoir.

Boatinfo - Mercruiser Service Manual nr. 17 - 1993-1997 - Engines GM V8 305 & 350 CID (5.0L 1993-1995)

Boatinfo - Mercruiser Service Manual nr. 17 - 1993-1997 - Engines GM V8 305 & 350 CID (5.0L 1993-1995)

Switches that will sound the alarm are item numbers 10, 6,
http://www.mercruiserparts.com/Show...g&inbr=2338&bnbr=70&bdesc=SENDERS+AND+SENSORS

And #1, http://www.mercruiserparts.com/Show...br=340&bdesc=OIL+RESERVOIR+BOTTLE+AND+BRACKET

http://boatinfo.no/lib/volvo/manuals/ef_efi.html#/140

 

[BIGALF]

Re: Engine alarm help

I don't want to do this before I get the scanner. I don't want to lose any data by disconnecting the wires.

 

[Fun Times]

Re: Engine alarm help

I don't want to do this before I get the scanner. I don't want to lose any data by disconnecting the wires.

I don't blame you, i would wait as well.

When you use the scaner, be sure to look for the not so well known genural warning 1 or 2. They are the indicators for the gear lube and transmission temperature when reading the scanner.

 

[BIGALF]

Re: Engine alarm help

Update on alam issue. I took the boat out for the third time today and it ran fine. It did not go into guard mode until after I ran for about an hour. I was going back to the dock and I stopped the boat and started it and all ok. I stopped the boat again and this time when I started it the alarm went on and the boat went on guard mode. the engine ran at low RPM.
Water temp and oil gage were looking fine. What do you think might be the issue. I am waiting for my service guy to get his scanner to check the codes.

 

[alldodge]

Re: Engine alarm help

I take it you didn't try doing what Fun Times mentioned in post 16 paragraph 3 ?