Thanks all. I've had this boat since 2014 . Never had closed cooling system before. It has run at 190 4 years now ....just having problem this year. I should have asked about 190 as a normal running temp years ago. Crap. Sure has me worried now. Will post update when I know more as to the fix.

I do not know if it has had a new sea pump housing. Will find out.

Need a IR temp gun to measure the thermostat housing. Gauges may or may not be accurate

Agreed on IR Temp gun but with steam coming out of the thru hull pipes I'm pretty sure gauge and alarms are working as intended. Thanks for your thoughts on this issue.

you can watch real temp with the scan tool. alot temp gauges at the dash are off with the readings.

Backflushing alone is not going to unrestrict cooling passages 100 fully. - alot of times you have pick out the blockage plus there is other forms of blockages in the cooling system. ie deformed gaskets, mineral deposits and aluminum oxide deposits especially in the cooling section of the cool fuel ( GEN 3 if applicable) also the check balls aka check valves cause cooling restrictions along with any kinked hoses.

You need describe the alarm, beeeeeeeeeeeeeeeep all the time

or beeeeeeep pause beeeeeeep pause

beeep beeep pause beeep beeep pause

the alarms all mean different things

It is so simple to rule out the gear oil bottle if that is your alarm - when the alarm is going off --- unplug the leads to the gear oil bottle - if alarm goes away then you found the problem, Just because the gear oil bottle is full of gear oil means nothing - the sensor / magnet pickup or float can be bad causing the alarm as well.

Mine are 2008 eight model HO with 400 hrs and just Sunday the port motor started the 2/3 second beep then pause then repeat beep. before shutting down i glanced at oil pressure and temp which were normal. we were at idle so water pressure was not really registering on the gauge. I had checked engine oil and drive lube the day before and checked engine oil and felt the risers after the alarm but no issues there. I failed to look at the drive lube bottle before taking it to the shop. I thought drive lube was a constant alarm??

Drive lube bottle horn is INTERMITTENT CONTINUOUS BEEPS. it is NOT a continuous horn. Those are more severe warning horns.

and again just because the bottle is full means nothing for producing a warning horn. Huge misconception by many.

is that what the warning sounds like for low drive lube or lube bottle senor? Or does that same alarm mean different things, I assume it will have stored a code?

bottle has the sensor in the bottom, it only has one alarm period.. You can set your own alarm off by pushing down the float all the way inside the bottle to test if it is working properly. Many boat owners drive lube sensor alarm do not work anyways because they never clean out the thick gel pudding of gear oil that has formed over the years .

Very easy to test the drive bottle alarm / sensor and the with just key on.

on scan tool it show under low drive lube strategy as a fault code

So I ll ask and I know as I am NOT asking to find out - so I will ask others --- what fault code number is this for pcm 555 ? Low drive lube strategy ??? Who will be the smart one here ?

fault 12

where did you come up with that fault 12 ? thats LOW OIL PRESSURE - motor oil ---- and that will set a guardian

I am going to stump the band here - or am I ??? PCM 555 - 496 low out drive lube warning is fault number what ???