I took out my 2000 Air nautique yesterday and had a problem with the temp guage. When i got to the river she fired right up and the temp gauge went all the way to the right and layed there. I put it in gear and just putted around, then suddenly the needle bounced back and settled @ 165 deg. After a quick stop at a sand bar, the problem reoccured, except this time the needle never bounced back. The red check engine light nor the do not operate above 1200 rpm light never came on. The heads/manifold areas didnt seem hot at all. All other dash gauges worked perfect. Any suggestions?