1990 Evinrude 60 HP overheating

I have a 1990 60 HP Evinrude and have been having trouble with the overheat buzzer. I am skeptical if it is actually overheating or if there is some kind of grounding problem. I have changed the waterpump and thermostat. I have also checked the temperature sensor and all work fine. I can run around all day at...say 300 R.P.M. with no problem. As soon as I surpass about 4000 R. P. M. the buzzer goes off and the power pack knocks me down to about 2500 R.P.M. If I slow down and touch the side of the engine it is not unusually hot (I can keep my hand on it for a few seconds). Water seems to come out normally from the little "**** hole". I also notice that when the buzzer goes off, or at high speeds in general, my tach and speedometer kind of goes haywire. So I don't know if it is a possible ground problem but I regrounded all of my gauges to both batteries but the same problems persist. I am kind of baffled at this point and was wondering if anyone here has run into similar problems. Any help will be greatly appreciated.<br /><br />Thank you

Re: 1990 Evinrude 60 HP overheating

What color is the temp sensor pigtail? Did you use OMC waterpump kit, which has improved impeller, pressure relief valve, and relocation of tattle tale nipple?

Re: 1990 Evinrude 60 HP overheating

Tach acting up could be a sign that your rectifier is on its way out.What does your volt meter read at 4000?I have no doubt that your engine is indeed going into the S.L.O.W mode because of a temp sensor signal and would check to see if your sensor has been upgraded as per Clantons post.

Re: 1990 Evinrude 60 HP overheating

You say, as soon as I surpass 4000 rpm the powerpack drops me to 2500.<br />It seems to me this is not because of too high temperature but because of speed.<br />To except a grounding problem I first would clean the powerpacks' ground terminal and apply some contact spray to the connectors.<br />If this won't help I would change the powerpack.

Re: 1990 Evinrude 60 HP overheating

clanton,<br /><br />The Pigtail on the sensor is a tan color...I did use an OMC water pump kit but it basically looked the same as the old one.<br /><br />Today, I checked the compression and found that the #2 cylinder was only reading about 75 psi (the others read about 120 psi) so I pulled the cylinder head and found some gouges in the cylender wall of the #2 cylinder. I guess that would explain why the engine has trouble idling properly, but how would that contribute to overheating? The head gasket looks to be in good shape with no signs of water leaking into the cylinders.<br /><br />Thanks

Re: 1990 Evinrude 60 HP overheating

Sounds like #2 leaned out probably because of fouled carbs and led to the scoring of the cylinder wall.Scoring = no lubrication = overheating.