I´m running a Beta 38 in a Willard 30 Motorsailer down in the Lesser Antilles Islands of the Caribbean.
Lately I´ve had some overheating issues. The details are as follows.
Current sea temp is 85*F
I normally cruise at 2500RPM giving me 6 knots (Hull speed is 7)
Lately the temp gauge is just below alarm temp of 210*F, last month while making a passage, after approx 4 hours running at 2500 RPM and slightly into waves/current it made it over the 210*F mark and ALARMED. I throttled back and put in neutral, and it cooled down quickly to 180*F (45seconds for alarm to go off and 180*F in 2.5 minutes) I brought her back up to 2500 RPM and finished the last 2 hours of crossing with the gauge staying just below 210*F and no more alarms.
about a month prior to this instance, I had some blockage in heat exchanger and a damaged impeller causing poor raw water flow, fixed those problems and flow is better but still pushing high temp alarms.
FYI. I can run pretty much long term at 2500 RPM and needle stays around 209*F.
at 3000 RPM I alarm after approx. 6 minutes
at 3500 RPM (WOT) It will alarm in 30 seconds.
In all these scenarios, once in neutral she cools back down quickly as stated above.
I´ve attached a couple excel sheets of engine temps and exhaust output as well as engine pic of where I take measurements with Infared temp gun.
