I had this issue with my 91 mercruiser I/O last year. each time I would come off of plane & idle into my marina, my port engine would start to overheat. not bad, I never let it climb too high, I would put the engine into neutral & rasie the idle, the temp would fall. while I proceeded into the marina on the starboard motor. it is a 1991 260 mercuiser with alpha I.<br />the outdrive was less than a year old when this problem occured. I had the entire outdrive replaced with a new unit(not reconditioned) & I installed a new waterpump at that time.<br />last spring(2005) before I put the boat in the water, I replaced all the bellows & the water inlet hose. I am wondering if the water inlet hose may be kinked & restricting the flow when @ idle.I had replaced the risers but not the manifolds on that motor. I had replaced the risers & manifold on the starboard motor though.I have new manifold to install on the port engine this weekend<br />I am looking for other possible ideas on what to check, before I put it in the water this year.
.....JK