496 overheating

[Butbro]

My 496 2008 still gives alarm when I go over 30, but temp gauge does not move much..
New waterpump but same problem.
What can I check next.?

See video.

 

[alldodge]

Could use your serial number

but, your motor has a temp sender for the gauge, and a ECT (engine coolant temp) switch which tells the ECM it's hot. The ECT is item 7 in link

https://www.mercruiserparts.com/bam/subassemblydetail/43086238/28188353

 

[Earl Cordova]

The water pressure switch on our boat has to be replaced every 3-5 years because it plugs up from the hard water in the lake we go to.

 

[ROY WILLIAMS]

My 496 2008 still gives alarm when I go over 30, but temp gauge does not move much..
New water pump but same problem.
What can I check next.?
MERCRUISER DRIVE UNIT GEAR.

exchanger engine coolant antifreeze 50% - distilled water 50%.
water pump parts MERCRUISER DRIVE UNIT GEAR