Have a Merc 50HP 2 stroke that is running smoothly and peeing water just fine. However, when running an alarm keeps going off. Plenty of oil in resevior. Any ideas what is going on?
Probably a bad sensor… I had the same problem with a 90hp merc I owned.
2007 Scout 221 150 Yamaha 4 stroke
It is a solid alarm.
Does it sound as soon as you turn the key on? if so and if equipped, its probably the oil alarm module. Look for a junction of tan wires with blue stripes, one of them will lead to a small black box. Disconnect the tan wire from the junction, if the alarm goes away, Thats your problem
solid alarm is only overheat i believe
does it happen as soon as you crank or does it take a few minutes?
The alarm comes on after the engine has run for a while. Typically it starts when I run up the RPMs. The water coming out of the pee hole is cool to the touch.
waterpump and thermostats, how long has it been since they were changed?