70 HP Yamaha - overheating

[CT-Kurt]

I have a 1986 70 HP Yamaha that I think is overheating. When run at idle for a while, the alarm sounds continuously. If I run a litle faster (maybe 10-12 MPH) while underway for a couple minutes the alarm will stop and the engine runs fine at high speeds. Water is continuously coming out of the small hole in the engine so I know the water pump is pumping something.<br /><br />Any ideas, or should I just change out the water pump and thermostat?<br /><br />Thanks

 

[Anymec]

Re: 70 HP Yamaha - overheating

It's easy to take out the thermostat and run the engine on idle to see if there comes enough water. Don't use it too long without the thermostat cover off. <br />Then you can try to run the engine without the thermostat, just put the cover back and run it to see if the alarm comes on. If it's OK, then change the thermostat.<br />You should also take a look at the impeller too.