85 hp heat problems

[maintmen]

I replaced water pump, put in new thermostats and poppet valves ., flushed engine,,,,,,,,, replaced one heat head sensor.

alarm,,,,,,constant,,, goes off above 4000 rpm on lake...... runs fine in driveway with a hose connected to it.

what else am I missing?

[boats.net]

Recheck water pump, inspect water pump housing and impeller closely for damage. Run a compression test to see if head gaskets are ok.