Merc 496 engine alarm has me stumped

LaRea

sandeka772 said:

... Our question is, can we cruise the boat home remaining at the lower speed without doing any damage to the engine?    

If it's the same issue I had (not enough raw water coming from the outdrive), yes you can go slow and it won't hurt anything.  

Have you considered getting a VesselView Mobile?  For $220, you can see engine data and alarm codes on your phone.  That should help you confirm the problem.  Your helm gauges only show coolant temperature.  The issue is a spike in Engine Manifold Coolant Temperature (EMCT) sensor.  

https://www.mercurymarine.com/en/us/gauges-and-controls/gauges-displays/vesselview-mobile/ 

https://www.amazon.com/Mercury-Marine-VesselView-Mobile-Connected/dp/B01MTGBKPQ

tricountytrail

LaRea said:

Problem solved at last!  It was a partial blockage in the raw water pickup hose inside the Bravo III.  See my summary HERE. 

I know this is an older post.
Question Now that you have your Simrad connected to your engines. (I chatted with you abit) you can not pull codes and display your sea water pump pressure on your chartploter, would this have helped find your problem quicker?

LaRea

@tricountytrail --- no, it would not have helped.  The engine never threw any fault codes.  I'd call it a blind spot in the system.  Also, at the time, I had two MercMonitors so I would have seen any fault codes.  

SimcoeRinker400

I Know this a older post my boat did that alarm thing to me on my last run last year.  Gave two alarms on the port engine.  Turned it off had the last beer of the year on the boat.  Fired it back up worked like a charm. 42 mph for a 400. Then she was pulled out the next day.  Do think the code would still be in the computer after a winter slumber?

Dream_Inn

Yes, code should still be in the computer to resurrect.

SimcoeRinker400

That's good news thought it be like my cars.

Ian

Check relays and connectors. I have been getting similar on port and after shutdown restart it goes away. But VVM said issue ECM talking to fuel pump and in my 2003 there’s nothing to talk to and my tech said it would be pump relay. 

tricountytrail

LaRea said:

@tricountytrail --- no, it would not have helped.  The engine never threw any fault codes.  I'd call it a blind spot in the system.  Also, at the time, I had two MercMonitors so I would have seen any fault codes.  

8/21/2022 913.73hous  PRT EMCT OVERHT Battery Volts 13.06      Sea Pump Pressure 13.07     Manifold Air Temp 120.20     Coolant Temp 177.80       3608 RPM   Found zebra muscles blockage in port engine water intake by transom this was why low raw water pressure and was getting worse.
Port intake 3/4 blocked at transom with corroded hose and broken insert.