While servicing the powerhead, the service manual suggests replacing the thermostats. Upon removing the cover, and to my surprise.............no thermostats were installed!!! How likely is it, that this may have contributed to the failure of the powerhead? Until now, all I can say is, carbon build up led to stuck piston rings in the #1 cylinder. If the powerhead was running below temperature, would this possibly cause additional accumulation of carbon deposits? Any thoughts?