Merc 40hp 4 stroke, EFI, 3 cylinder

[Bill U]

My motor starts easily. After 2-3 minutes running at 4K rpm's, the motor loses power and either kills or it idles and runs real rough. If I wait for the engine to cool off, it starts up again and repeats the same thing. Does anyone have any suggestions?

 

[kjacks]

I would say it is overheating. It has a built in system to limit revs when the temperature gets too high until the problem is corrected. Once it cools off, it will repeat if not fixed. Check your water flow, thermostat, and temperature sensor.

 

[Mikey N.C.]

Does it have a small portable tank with fuel demand valve?