Alarm on 496 MAG HO &power reduced but all temps and levels look good??

[CAMELLA]

I was having the same issue on engine 1 and Sea Ray replaced the water pump and all issues went away. The boat ran fine until I came off plane and that's when all the engine alarms would go off.
All the gauges displayed good temperatures, it was the manifold heating up which was due to not enough water flow once coming off plane.

 

[BillZ]

by coming off plane you mean slowing down and not being in plane correct? also what pump. the sea water pump or the water circulating pump?

sorry but Im new to owning a boat and to boating ..

 

[CAMELLA]

Coming of plane to a no wake zone is when the alarms would go off. The salt water pump is the pump they replaced.

 

[BillZ]

Thanks to all for the help. Received my scan tool today and its telling me low oil pressure. 3.1 psi yet my gauge shows a steady 40 psi.

disconnect sensor and of course alarm is gone. Question now is which reading is correct. If the pressure was so low wouldn't I be over heating?

could a quart low cause this?

Would like some info on this sensor... searching but cannot find the following:

part # for oil pressure sensor? (merc 496 MAG HO 425 HP)

what size socket to remove it.. its in there deep and is larger then what i had available... over 3/4. is it metric?

although scan tool says it will test sensors I did not see any way of doing so. with sensor connected scan tool gave me code for oil pressure and showed it to be 3.1 psi and with sensor disconnected no code and shows pressure as about 50 psi ( dash gauge always at 40 psi).

Thanks