Optimax 135 hp steaming

[Recius]

Hi there everybody!.
When i went out the other day with my boat i noticed that temperature was really stable (40 degrees celsius) as long as the engine was in high speeds.
When i was trolling the engine began to rise temperature toalmost get 80 degrees celsius and some steam appeared.
The alarm didnt appear but i consider that temperature high

Anyone can help me? Any ideas if the impeller is in bad shape or maybe de thermostats?

[JOE54]

I would replace w/p and all 3 gaskets and new thermos too if its been over a year since they were done , alsolook in v6 section one down for more info on your engine and use ser number please sir