Home › Forum › Ask A Member › Overheat alarm on Pa-in-law’s Evinrude? › Re: Overheat alarm on Pa-in-law’s Evinrude?
Don’t think so, the thermostat has a vent hole, and the block is vented through the overboard indicator hose. 5-10 minutes is plenty of time for that engine to heat up enough to sound the alarm. Keep in mind the hot weather we have been having doesn’t help, like I say, those engines run pretty hot at idle to begin with.
Try revving the engine in neutral (no more than 3000RPM) while the overheat alarm is sounding. Increasing RPM like this pushes the cooling relief valve off its seat allowing more water to bypass the thermostat. If the alarm shuts off while the engine is revving in neutral, then most likely the alarm is telling the truth. It should only take about a minute or so for the engine to cool down some (enough to kill the horn) while revving with the relief valve popped off its seat.
But again, the hot temps down there might just be to blame. You mentioned that this problem only occurs once, then it is fine for the rest of the day.