1997 YAMAHA PROV 175 Alarm goes off

[ivb53]

After running engine for 10 minutes at various RPM's, alarm goes off, engine throttle is cut back. Certified YAMAHA mechanic cannot figure out why. It is not overheating 150-160, Have replace Thermostats. Propeller was also replaced. Does anyone know what could be causing this? Also, does anyone know what temp it is designed to kick off? HELP! Thank you.

 

[99yam40]

do you have gauges that tell you if it is getting an alarm?
Does the buzzed work and does it sound when this happens?