Runs too cool

[Dave]

The engine in my 77 Catalina 27 runs too cool when the hull valve is fully open. I have replaced the thermostat and gasket. The block and thermostat cover surfaces look ok. It appears the water is still getting by the thermostat. The only way to get the engine to run say 140 to 160 is to partially close the inlet ball valve.

Any suggestions?

Dave

[Don Moyer]

Dave,

It's difficult to conclude anything other than that your thermostat is not closing completely.

I'd remove the thermostat try to breathe through it. It's difficult to see if a Westerbeke thermostat is 100% closed due to the fact that the valve itself is in a deep recess. In quite a few cases, a thermostat looked closed, when in fact we were able to breathe through its operating mechanism.

Regards,

Don