"Ken, With proper care and if
"Ken, With proper care and if it is in ok condition now, this engine will outlast you and me together. Use only DELO 100 SAE 40 oil or other brands explicitly approved by Detroit for these engines. MULTIGRADE OIL WILL KILL THEM (this applies to all DD 2 strokes). The current condition of the engine can be assessed by how it starts up cold. After a cool fall night the engine should start up after the first couple of crank turns. Some white smoke that clears up within a minute or so is OK. Hard starting when cold, prolonged white or even blueish smoke is an indication of tired cylinders. This is where the major benefit of DD's comes in. The cylinder liners and pistons can be replaced as kits with nothing but hand tools while the engine is in the boat for about $1200 to $1600 in parts. (Try that with Yanmar or the like). Some people knock Detroits for being noisy and dirty. Soundproofing the engine bay and understanding the function of the airbox drains goes a long way for changing your attitude to: ...You hear that? Do you hear that? Detroit, son. Nothing else in the world sounds like that. I love the sound of a Detroit in the morning." If you need more HP, change to N50 injectors ($65 a piece) that will give you 210hp @2800 and still more life than you and me together)"