Mercruiser engine alarm beeps and engine shuts off

[pat8839]

Thought I would run this by you more experienced and knowlegeable guys...

First off, I have a 2006 4.3L MPI Mercruiser with Alpha 1 outdrive. It has approximately 500 hours on it.

Took the boat out yesterday, we wakeboarded, sat on anchor with the boat off, wakeboarded some more-all no problems.

THEN, we started back toward the dock and as my fiance put the boat in gear there was the "beep" and the engine shut off. The sticker on my boat says the beep sounds for high temp (temp gauge read 170*), low gear lube (this level is fine), and low oil pressure (my oil pressure was just below 40).

I could get the boat to stay running if I disengaged the prop and just gave it gas but when I brought the throttle back to neutral to then re-engage the prop to move the engine would beep and shut off. I was able to get back to the dock by immediately putting the boat in gear and staying just above idle speed, however the beep did sound every now and then (I did not know enough to pay attention to how often it beeped) but it did not shut off again until I backed off to idle speed when we got to the dock.

Any ideas? I have read a few things suggesting that perhaps I have a problem with my idle air control. I've no idea how to check that...

Thank you in advance!

 

[Don S]

Re: Mercruiser engine alarm beeps and engine shuts off

Not sure about the alarm, but the MPI does not shut the engine down completely. Reduced rpm yes but it will not shut the engine off.
The alarms you listed are only for the alarm, and have nothing to do with the engine running or not.
I would suggest you hook it up to a diagnostic computer and find out what happened. Can you repeat the problem on muffs out of the water?

 

[pat8839]

Re: Mercruiser engine alarm beeps and engine shuts off

When I got back to the house I went to run it on the muffs but it would not stay running-it would do the beep and shut down. I was too afraid to force it to stay on like I did in the water.

 

[maicoman]

Re: Mercruiser engine alarm beeps and engine shuts off

Hi I have been having the same problem with an older 305 mercruiser.People say the IAC is the place to look but mine was not the problem.I am in the middle of a long trial and I am looking at the fuel pressure as my problem.I have a computer but my ECM is not setting a code.My motor has a vacuum line from the pressure regulator to the throttle body.By carefully squeezing the hose you can tell if the pressure builds in order to keep the motor running.Fuel Pressure Sensor and Fuel Pressure Regulator is where I would start.Have someone put a computer on yours and if everything comes up fine tell them to test the fuel pressure.

 

[pat8839]

Re: Mercruiser engine alarm beeps and engine shuts off

Maicoman, thanks for the idea! I will check that out

 

[maicoman]

Re: Mercruiser engine alarm beeps and engine shuts off

The problem you are having is related to the shift interrupter switch on the shift plate.Disconnect the 2 wire switch and use a jumper wire to short the 2 wires to the computer.The motor will now idle just fine.Either your switch is broken or the cable is misadjusted.Don't ask how I know !!!!!

 

[Don S]

Re: Mercruiser engine alarm beeps and engine shuts off

A broken shift interrupt switch will keep you from getting the drive back into neutral when in the water, and if broken, will not stall the engine, and has nothing to do with the alarm system.

You need to get the engine hooked up to a diagnostic computer and check things out.

 

[Pete104]

Re: Mercruiser engine alarm beeps and engine shuts off

He has jump A to C on the engine side of interupter switch harness. Do this AFTER you away from the dock if possible. Whoever is operating the boat, has to realize, manuverability is compromised. The interupter is on an MPI, different than it used to be. I went thru this awhile back & Mercury sent out a new ECM.

 

[Fun Times]

Re: Mercruiser engine alarm beeps and engine shuts off

He has jump A to C on the engine side of interupter switch harness. Do this AFTER you away from the dock if possible. Whoever is operating the boat, has to realize, manuverability is compromised. The interupter is on an MPI, different than it used to be. I went thru this awhile back & Mercury sent out a new ECM.

That was more of an 2003/04 problem than a 06 problem. We would need his serial number to know for sure though.

SMC-03-06 - V6 AND V8 GMEFI WITH NO START, ENGINE MISS-FIRE OR ENGINE SHUT-OFF CONDITIONS

 

[pat8839]

Re: Mercruiser engine alarm beeps and engine shuts off

Hey guys thanks for all the advice.
Here is my update...
So last weekend while I was waiting for the weekend to pass so that I could call a mechanic on Monday I was tinkering around trying to find a possible problem. Well I had read somewhere that the IAC (Idle control valve) could be the problem. So I took the IAC off and tested it. Resistance should have been somewhere around 7ohms but it was 0ohms-meaning it was dead. I hooked it up to power from the battery and the valve never shifted. So I ordered a new one which came in the mail last night. I installed it and voila! She runs and I am back in business! (I also replaced the gasket and IAC muffler thing) Bad on my part I know, but I did not have a mechanic check it out because everything I read in the manual pointed to this IAC and when I found it to be dysfunctional I prayed that was the case. Had that not worked, mechanic would be coming today...Maybe this will help someone that runs into the same issue. Finding, testing, and reinstalling a new IAC valve is a piece of cake!

The new part is so shiny!

 

[Don S]

Re: Mercruiser engine alarm beeps and engine shuts off

That would have showed up on a diagnostic computer.

 

[Rivcruiser]

Re: Mercruiser engine alarm beeps and engine shuts off

The problem you are having is related to the shift interrupter switch on the shift plate.Disconnect the 2 wire switch and use a jumper wire to short the 2 wires to the computer.The motor will now idle just fine.Either your switch is broken or the cable is misadjusted.Don't ask how I know !!!!!

You are a GENIUS! I had this very problem. The shift plates, and switches, had been repleced with newer ones. The problem was...the new ones were open in neutral, and the old ones were closed. Because of that at idle...the engines ran at the shift rpm and stalled. Thanks again.