I know this is an engine topic but I like this forum better 
Anyways why do you have to replace pistons if they have some vertical scoring from overheating? I can understand that the cylinder walls of the powerhead should but if a piston has some scoring like on the lower half of the exhaust side how is that going to effect the performance of the motor? There would still be a significant amount of surface that isn't scored and the piston would remain straight throughout the stroke right? If I rehone and replace the rings and use a new clean block why couldn't I use the same pistons over again? Can someone dispel this ??? for me?<br /><br />I inherited a small Evinrude 9.9 and it was overheated by a lack of water cooling. I took the powerhead off and saw the exhaust side scores. Gonna fully crack into tonight.
Anyways why do you have to replace pistons if they have some vertical scoring from overheating? I can understand that the cylinder walls of the powerhead should but if a piston has some scoring like on the lower half of the exhaust side how is that going to effect the performance of the motor? There would still be a significant amount of surface that isn't scored and the piston would remain straight throughout the stroke right? If I rehone and replace the rings and use a new clean block why couldn't I use the same pistons over again? Can someone dispel this ??? for me?<br /><br />I inherited a small Evinrude 9.9 and it was overheated by a lack of water cooling. I took the powerhead off and saw the exhaust side scores. Gonna fully crack into tonight. 
