I have just repowered my Sea Ray 350 EB with two Yanmar 6BY2 260Z engines.
Specifications for the thermostat is start opening at 88 C(190 F) and fully open at 96 C (206 F).
When I drove the boat at 3600 rpm, temperatures was at 99 C. Yanmar engineer said 6BY2 operates at high temperatures and that is normal.
Does anyone can share similar experience in using Yanmar diesel engines?
Thanks a lot.