we needs some help

[penalty box]

I don't think I would worry about 140 going to 160 if it keeps going up I would, my older boat did the same thing, when the engine temp started to rise I would put it in neutral and rev it up for about 30 seconds and it would go right back down, I would do this about every 1/2 hour.

[wakina]

Might want to check the thermostat, it might not be opening up all the way and restricting the water flow at slower speeds. I have had a similar problem in the past and the issue was resolved with a new thermostat, scale had built up and it could not open and close properly.