Water Pump/Impeller Question

Hi, I have a 3.0L Mercruiser. I was boating the Mississippi through DT Minneapolis yesterday and I noticed fluctuation in my temp guage. I just bought the boat and this is the third time I have had it out. The temp guage usually reads about a quarter of the way up (I think the middle of the guage reads 160?). The guage has mostly been reading in at the first quarter reading mark unless I'm idling, in which it will go up to halfway. Yesterday, as I was cruising back to the trailer, I saw that it was reading at the halfway mark, which it hasn't really done before. It didn't overheat but it made me sweat a little. It's about winterizing time and I'm wondering how I know whether to replace the impeller or the whole water pump. I've never done this before but I have the manual and a some aptitude. The outdrive was serviced 5 years ago (changed seals and impeller) and the boat wasn't used much the last two years. Am I being overly cautious? How do I know the impeller is bad?

Re: Water Pump/Impeller Question

Your impeller should be replaced every other year period. If you use the boat it wears, if the boat is parked the rubber vanes will take a set and not flex out far enough to be very useful.

Re: Water Pump/Impeller Question

Thanks. What about the actual pump? Also, is this a pretty quick procedure? I have the manual but since I haven't done it before...

Re: Water Pump/Impeller Question

Follow this link to the adults only section and from there find the area for Merc outdrives. The late DonS put a whole bunch of stuff there to help us all. If after review you have specific questions come back and ask them

http://forums.iboats.com/mercruiser...tdrives/adults-only-no-exceptions-288430.html