Took my 2005 first voyage yesterday. The water temp gauge was not showing any temp. <br /><br />Water temp was 56F. I have an 160F stat -- original stat.<br /><br />Since I do my own maint, first thing I did was shut it down and pull the stat to make sure I didn't forget the gasket with the rivets or put the stat in upside down.<br /><br />Everything looked good. Put it back together and started it back up. I had my IR temp gage and I started reading temps. On the block adjacent to the tstat housing was 140F. The tstat housing was 80F. The one piece Merc risers were 95 to 115F depending on where I took the measurements. Oil filter temp was 180 to 190F.<br /><br />I took it on a 60 second run and rechecked temps -- same. Took it on longer and longer runs and checked temps again -- same temps. At the end of a few minute 3000 rpm run the water temp gage on the dash quickly climbed to 160-170F at idle. After a minute at idle, I gave it throttle and the gage shot back down to < 100F. Another time, the gauge started to climb during a run, it got to about 120F, and then went down to <100F -- the lowest on the gage. That is all I saw on the gage that day. Put about 30 minutes on the engine puttering around.<br /><br />I wiggled wires around the temp sender and alarm temp sender on the stat housing, but if the stat housing is 80F, I doubt it is an electrical problem of the gage or senders.<br /><br />Maintenance: last changed Alpha 1 Gen II impeller in the fall of 2004; 175 total fresh water hours on engine/boat; original tstat -- Merc 160F. Other than regular meticulous DIY maintenance with Merc manuals, everything else on boat is original.<br /><br />First thing I am going to do is get a new tstat. I know I shouldn't just throw parts at it, but the old one is a little rusty and I figure I could use one sooner or later.<br /><br />Where should I go from here? Am I missing anything from a procedural or troubleshooting standpoint?<br /><br />Thanks for your help.
