I just recently (early April) bought a boat with a 98 40hp Force by Mercury Marine outboard on it. The motor seems to run fine except that I am not sure it is cooling properly. At idle almost no water is coming out of the exhaust port. There is just a little bit spitting out. At full throttle there is a good amount of water coming out. However, I have noticed that after long periods of full throttle running and then returning to idle it seems like there is some steam coming out of the exhaust port with the water. <br /><br />I replaced the impellor with a new one with no improvement to the condition. <br /><br />The cylinder head is not too terribly hot but I don't know how hot is too hot.<br /><br />What is the best way to diagnose this condition? Can I get a water temp gague on this? Where would I install it? <br /><br />Any help is appreciated and sorry for the long post.
