merc 1.7 diesel

[outbdvstern]

Has anyone had experience with or know about the reliability/performance/longevity of the Mercruiser 1.7 liter diesel? Its a 120hp motor with an aluminum head, is lightweight and connected to the Alpha series outdrive. The intended application is on a 28 ft ProKat, twin engine installation, saltwater use - almost exclusively offshore. I am told it will get about 4 miles to the gallon. They move the boat along between 37 and 41 mph. The engines are crammed into a small space, which means if and when work is needed on these motors, its going to be expensive. The other power options are the 200 or 225 hp four strokes, but fuel economy is supposedly around 1.9 mpg.