I have a 1980 2QM15 on my Hunter 30. It is a great little engine and I have had no problems over the past 8 years. It is sensitive to fuel
flow problems so make sure you bleed the lines
when changing filters. Bleeding is easy since there is a bleed screw on top of the secondary filter. The engine is raw water cooled so it does not get very hot - hence you cannot heat water for your galley. There is no engine kill lever - so just decrease the throttle until it dies. There is no tachometer but you can add one run off the alternator. There is no temp gauge so ake sure the cooling system is working well. I would change the: impeller, thermostat, hoses, belts, zincs, temp sensor and oil pressure sensor, and air filter, on an old engine like that.