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Continuous alarm when accelarating either mercruiser engine

 
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blups



Joined: 20 Oct 2007
Posts: 7

PostPosted: Sun Oct 21, 2007 8:40 pm    Post subject: Continuous alarm when accelarating either mercruiser engine Reply with quote

I have twin mercruiser 6.2mpi Horizons and am getting a continuous alarm when accelariting out of idle sometimes. Oil and temp look perfect and engines sound very heatlhy when running at any rpm, but as power is applied from idle the continuous engine alarm goes off a little after 1000rpm and only stops when power is brought back to idle. However, if I re-apply power immediately they run fine all the way to 5000rpm fo hours I suspect until power is brought back to near idle and the process starts over. The weirdest of all is that it could happen to either engine, even if the other is off, and even sitting at the dock and reving them up independently. The engines also run very rough if I try to accelerate through the alarm as something in its "brain" probably gets confused and starts cutting the fuel injection. I saw a posting from someone with a similar issue, an he was going to replace the IAT sensor, but did not say whether it worked for him. Also since I get the alarm in either engine I suspect the problem is farther down the line on its way to the alarm, and not in the engines themselves. Is there any sensor that could be faulty that gets reading from either engines? An amp meter maybe?
Thanks, Bruno.
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boatScotty
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Joined: 07 Nov 2006
Posts: 229
Location: Pacific Northwest

PostPosted: Mon Oct 22, 2007 9:30 am    Post subject: Continuous alarm when accelarating either mercruiser engine Reply with quote

The simple answer on this one - is you need to get your engines hooked up to a computer that tells what is happening in the electricary (misspelled on purpose!) or otherwise.

You sound like you are in the scary place of dollars to find out what is not talking to what OR dollars for parts until you replace the right one (or combination of ones!!).

I hope someone comes back with exactly the same problem and what they did!
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Boat Scotty

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MikeW
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Joined: 01 May 2006
Posts: 680

PostPosted: Mon Oct 22, 2007 4:05 pm    Post subject: Continuous alarm when accelarating either mercruise Reply with quote

Hello Bruno, can you supply us with the engine serial number? There are a couple of things I would like to look at. The engines have separate monitoring systems.
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blups



Joined: 20 Oct 2007
Posts: 7

PostPosted: Tue Oct 23, 2007 6:38 am    Post subject: continuous alarm when accelerating either mercruiser engine Reply with quote

Sure, its OW062776 and OW062775. Thanks for the help!
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MikeW
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Joined: 01 May 2006
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PostPosted: Mon Oct 29, 2007 10:21 am    Post subject: continuous alarm when accelerating either mercruiser engine Reply with quote

Hello Blups, we are looking into your serial numbers and will get back to you in a day or two.
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blups



Joined: 20 Oct 2007
Posts: 7

PostPosted: Mon Oct 29, 2007 6:25 pm    Post subject: Reply with quote

great. its puzzling me. I did find out that if I try to accelerate i will get the alarm just above 1000rpm but if i bring the throttle back to idle until it quiets then quickly re-accelerate it won't come back on, so I used the boat this weekend using this method. Its really anoying though.
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blups



Joined: 20 Oct 2007
Posts: 7

PostPosted: Mon Nov 12, 2007 3:01 pm    Post subject: Reply with quote

So I've isolated the problem to only one engine, not both, but the problem is happening more often now and its causing the engine to stall when in idle. When the alarm sounds, it also makes the engine run rough, probably becuase its trying to cut the fuel. If it does not sound, it runs perfectly. Don't know where to start
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MikeW
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PostPosted: Mon Nov 12, 2007 3:19 pm    Post subject: Continuous alarm when accelarating Reply with quote

Hello Bruno, do you have Throttle Body injection? If so, it sounds like the Idle Air Control Valve is going out.
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blups



Joined: 20 Oct 2007
Posts: 7

PostPosted: Mon Nov 12, 2007 5:38 pm    Post subject: Reply with quote

Would that make the alarm go off? And could that happen at higher RPMS 's as it does, like 3000? If so, how can I troubleshoot to see if it really is the case? maybe swap from the good engine?
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MikeW
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PostPosted: Tue Nov 13, 2007 9:02 am    Post subject: Continuous alarm when accelarating either mercruiser engine Reply with quote

It could set off the alarm but not affect high rpms. What type fuel injection do you have?
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blups



Joined: 20 Oct 2007
Posts: 7

PostPosted: Tue Nov 13, 2007 10:24 am    Post subject: Reply with quote

I'm not sure. Its an 05' model and from the drawing it says "mechanical body and shift". I did find the air valves in the drawings but I do get the problem in higher revs so it still be the idle vale? Again, bringing throtle back to idle and reincreasing power has been resolving the issue so far.

Last edited by blups on Tue Nov 13, 2007 10:44 am; edited 1 time in total
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MikeW
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PostPosted: Tue Nov 13, 2007 10:43 am    Post subject: Fuel injestion type Reply with quote

Hi Bruno, if you have multi port injection there will be eight injectors on two fuel rails. One rail located on each side of the intake manifold. If you have throttle body injection it looks similar to a carburetor.
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blups



Joined: 20 Oct 2007
Posts: 7

PostPosted: Tue Nov 13, 2007 11:03 am    Post subject: fuel injection type Reply with quote

I have the MPI
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