My 142E does the same thing -- the temperature gauge always sits at or above the 3/4 mark, whether it's 20 below zero or the 90 degree weather, and I have a new water pump -- never boils over though. I'm not sure what the thermostat is rated at, but whatever it is, I'm going to put one in that is 10 degrees lower, just to see what happens. You could give that a try as well. I'm with the others, leave that pump alone. If you are going on a long trip and don't feel adventurous, take a spare. If they are gonna go bad, they usually give you fair warning. Replacing them is an easy road-side repair. My main reason for saying this that, invariably, whenever I start messing with the water pump I end up with leaks elsewhere, like where the heater supply tube goes into the pump -- even with new seals. Old engines have valuable bits of crud accumulated in strategic locations. My philosophy is to leave them in peace to do their job of keeping that old hunk of iron healthy. ;-)