[JohnB]

With average maitenance, ob motors last a long time. The only new thing is alcohol, and it is killing a lot of older 2 stroke carb and tbi efi motors. Crud in the fuel system will lean out a cylinder and than you got problems. I had a merc efi with over 2500 hours on it that ran like a top until the crank broke. I think most 2 strokes will get to 2000 hours with maint. I am not sure on the 4 strokes, more moving parts. The SeaTow guys around us are running Suzuki 4 strokes and replace them every 2000 hours and don't seem to be having any problems with them. Time will tell. Suzuki warranteed mine for 6 years, and I average 350 hours a year.