Engine Warning Alarm

[Strikeliner]

I wonder if anyone can help? Whilst driving my Mercruiser 5.0l powered boat ( Maxum) recently the audible engine alarm sounded. I had been travelling for about 10 minutes or so at about 3200rpm. I immediately stopped and checked all the dials. They all showed perfectly correct readings and the alarm stopped. I decided to continue for a while at about the same speed and noticed that after a while the temp guage moved from a normal reading towards the left hand side of the dial i.e indicating a lower temperature. A reduction in revs very quickly caused the guage to move back to the normal reading!!!!!??????
The engine performance seemed fine. Oil level and gear lube levels are correct and there was no other apparent problem apart from the engine alarm sounding. Could this be a faulty guage or sender causing a duff reading and consequent alarm? The engine has run for less than 100 hours and works fine in every way. If anyone has experienced this or similar Iwould be pleased to hear.

Steve

 

[ColinHuggins]

Alarm for what exactly? Alternator charging? Oil pressure? Cooling water flow? Or temperature? Exhaust temperature? Bilge levels?

Oops, must keep my eyes on the road . . .

 

[david_bagshaw]

your explanation sounds a likely possibility, along with a poor / intermittant earth.

a failing impeller might give a poor flow at the higher power to cause the alarm as well

 

[Strikeliner]

Thanks for the replies.

The alarm warning sounds for one of three reasons. Oil pressure, temperature and alternator. Keep Chuggin.

All these readings appeared to be sound when the alarm activated.

The earth connection sounds a likely source. Thank you David

Steve

 

[spannerman]

You say the engine has run for less than 100 hrs, but how old is it, if its more than 2 yrs it could be time to have the impellor changed as it sounds like the cooling is RPM dependant which tends to point the finger at the impellor, it could be the thermostat playing up too, I'd check it before lifting the boat.