Hi I have a 2001 Mercruiser 7.4 MPI with Bravo 3. On the first day of the boating
season I noticed an overheat alarm
. The temperature on the gauge was approximately 170. I slowed the boat
down and it fell quickly to around 150 and the alarm
stopped. I have a MEFI gateway which shows the engine
data so this alarm is being logged by the ECM.
I took it out again and noticed the alarm is going off when the temperature rises above 150. Now in the spring I had the manifold and risers replaced and after the overheating
I had the sea water pump
with inside impeller, thermostat and temperature sender all replaced. I am still getting the alarm.
I have looked at the engine service
manual and it doesn't make clear what the maximum operating temperature is and what temperature should the alarm go off on. Also last season after a long trip I have screen
shots where the temperature gauge is sitting at 170 but I didn't get any alarm. As a matter of fact prior to my first trip the ECM had no logged engine temperature events
in its history
yet I ran at 170 many times.
Any ideas as to what the maximum operating temp of a Mercruiser 7.4 is and what should trigger the alarm?
Any possible ideas as to what could be causing overheating
(if it is really overheating) would be appreciated. Checking with an IR gun the temperature of the hoses are in the 160 range when the alarm goes off and I can hold my hand on them so it doesnt feel like its overheating. The manifold and risers were at 130.
Any ideas would be appreciated.