Westerbeke
We too have this engine in our H-31. With some 1400 hours on ours, I can report no problems. It consumes half a gallon of fuel per hour at 6 knots +, uses no oil, always starts, has self-bleeding fuel system (a real bonus) and has needed professional maintenance only once (to replace the exhaust elbow that rusted through). I replaced the oringnal raw water pump this year when it began leaking. I will rebuild the original and keep it as a spare, though I doubt that I will ever need it. Water temperature is usually just over 180 on the gage, and oil pressure over 60, but I really don't think the gage is that accurate. I have never heard of a rebuild on this engine.I have found traces of antifreeze here and there intermittently since new. I think the cooling system air bleed cock is the source, but have never really been able to trace it. The occasional drippy hose connections may also be the source. I have had to put antifreeze into the expansion tank occasionally (without consistency), but think that this is often a function of air finding its way out of the cooling system. On the H-34, engine access could be better in that the raw water pump impeller is a bear. I usually inspect it by rmoving the cover and using a mirror. Removing the alternator and the pump is probably the easiest way to replace it. Keep spare water pump gaskets and an impeller. I find they last two to three years under my 100 hour per year usage. I guess that's about all I can report. Its a decent engine, though somewaht heavier than the Yanmar that replaced it later in the production run of '83s.