Well I am trading my 99 205V in on a new Malibu in a few days. I went out to the lake to take one last spin before I got rid of her. Well de winterized the boat and started great blah blah. <BR> <BR>Well I was going down the lake and I noticed the temp was at about 200 (usually 160). I backed off shuter her down to check the engine. Felt the block and the temp was not abnormal to the touch. The manifolds were warm (normal temp)I could keep my hands on them for a long time without burn ring. So all inspections check out. <BR> <BR>Fire the boat up and the temp read 180ish. Idle down the lake and the Temp goes to 160 then back to 220. Just a constant dance back and forth. The impeller housing was completely cool also. So I just idled back to the ramp put it up. Also if I raised the RPM the temp stayed more on the higher end. I have always found that temp will go down 5 degrees when the RPMs are higher (because there is more cool water running through. <BR> <BR>OK please feel free to ask any questions but anyone have any suggestions? <BR> <BR>Thanks <BR>Preston

could be a bad ground on the gauge.

Agree with Matt. If your impeller was fried, the boat would be hot at idle and cool down when the speed increased as the water would be forced through. <BR> <BR>Your thermostat could be messed up, not opening up at low enough temp. Start with the easiest stuff if you wanna fix it, check the impeller, then the gauge.

sounds like a thermostat problem to me..

You might want to fire it up on the trailer with a "Fake-a-lake" and verify that you get a reasonable amount of cooling water flowing through the system. <BR> <BR>Then I would go ahead and change the impeller. Probably time anyway. <BR> <BR>Rod

I betting on the bad ground connection. Run a test wire directly from the ground on the back of the temp guage to the battery and see if the problem still exists.

Trade it in and start worrying about your new boat.

I had a piece of the impellar break off and block the water flow periodically. It was doing the same thing you describe. I thought it was the thermostat because it was infrequent. It kept doing the same thing after I swapped the thermostat out so I finally pulled the empellar housing apart and sure enough broken piece of it stuck in the exit of the housing.