H30 water heater
If your engine is raw water cooled, like mine, the engine really doesn't get hot enough to tie into a hot water heater (only 135 degrees). These engines run cool so as to not distill all the salts out of the cooling water and clog the water passages. Don't put a hotter thermostat in it, assuming you could find one.If your engine's got a heat exchanger the engine doesn't come in contact with the raw intake water and it runs hotter, around 185 degrees, and will work fine for producing hot water.Some folks have retrofitted their raw water cooled engines with heat exchangers, but (suprise, suprise) it's an expensive project.