Re: 1996 mercury 75hp 2 stroke thrown rod
90% are lack of lubrication. This can be from a carb jet stopped up causing cylinder to run lean, water intrusion into a cylinder, overheat damage. What happens is aluminum from piston is transfered to cylinder wall which eventually causes siezure of that cylinder. The other cylinders overcome the stopping force and siezed rod snaps. The other 10% are incorrectly propped (to many rpm) and lugging.
