I was out fishing today and my motor overheating siren came on when we started heading back to the boat ramp after using the boat all day. The motor was pumping water good and had plenty of oil. My buddy who knows a lot about Yamaha's said it sounded like the thermostat was bad. Does this correct to you fellas? If so, where is the thermostat on my outboard and how do I replace it? My buddy told me it wasn't a very expensive part. Thanks ahead of time for any answers.