HI. I need some advice on a 1985 mercruiser i/o v6. It was running fine when put in storage Nov 07. Didn't get it out in 2008. This year I'm paying the price...had to have the carb rebuilt, and trailer brakes & bearings serviced. My final problem seems to be overheating at low speeds..i.e. when trailering or troller -- RPMs under 1,000. I used to be able to troll at 600-800 rpm for hours, but now it will overheat (over 200 degrees) after a few minutes. Speeding up brings it back down to 130/140 degrees. It seems to run fine, except for the overheating. Is this an impeller issue, or something else?