I have 2005 twin 525EFI's. I am getting 3 alarm beeps about 1 minute apart. Has anybody experienced this? A sensor of some sort??

Yes it's a sensor, your going to have to scan it to see which one

3 beeps indicates a warning. First you need to isolate which engine is triggering the warning. Turn the key on one engine at a time and see if the beeps persist on that engine. If the beeps persist and don't stop by turning the key off and on again, then the system is detecting that there is a failure of some sort somewhere. 3 beeps is usually an indicator of a sensor failure (ie: water pressure or temperature, oil pressure or temperature). It's pretty easy to figure out if you can get someone to hook up a scan tool; otherwise you're going to be guessing which one.

The beeps are like the check engine light on the car some sensor is reporting out of its parameter range or ignition related. A scan is needed of your engine. The current software that can scan Merc racing apps is needed. Diacom or, Merc G3.

www.rinda.com
You ought to buy a scanner. Best money you will spend on that boat.

It's the Starboard motor. I took it to the dealer this morning and they hooked it up to the computer. A couple old codes (50-60 hrs ago) but nothing new. They called Mercury and they don't know what it is either.

Did they look at active faults or historic?
You have a great dealer if you whipped in for a quick check and they accommodated you like that; especially if they put it on the hose, and ran the motor with the computer attached.


Swap the IACs from one motor to the other motor. Common failure. See if the problem follows the swap.

mercury is not going to say I don't know - they would have thrown out something even if it was a total 100 % guess - I promise they always do.

You need to post info what the engine is doing running thru out the rpms - can you achieve max rpm's, does it idle smoothly or rough, easy start or hard, accelerates normally ? Stalls - will not restart easily and so on and so. You posted a dart board and the only answer you are going to get is the darts. More info is needed. Year model and engine serial would be good as well.

Dealer clears old codes (low drive oil reservoir, block water pressure low) and now the block water pressure low code came back. He disconnected that sensor but the 3 beeps still occur. His plan now is to start disconnecting each sensor one by one to try and isolate the problem one.

The engine is running fine. It starts good, idles normal, nothing out of the ordinary. I was out and it ran fine for 3-4 hour yesterday but it started to beep as I came to a no wake into the marina to load up. Originally I thought it might be a little low on drive oil so I didn't look at it until I got home. Fluids were all good. Even going slow into the marina, it didn't sound any different than normal.