Reply To: 1962 Johnson 10 hp

[frankr]

Look at the wrist pins.  The “weakness” was the pin diameter.  The smaller pins would beat out the hole through the pistons and become very loose.  Incasing the pin dimeter gave them a much larger contact surface area inside the hole Also note the wrist pin bearings, The new ones were huge in comparison.  in fact, they are the same bearings as used in the 40hp and V-4’s.  BTW, the ’61-’63 parts can be used in the older motors.  But you have to do the whole thing—pistons, rods. wrist pins, snap rings, and bearings,  If you look at the parts list for the older pistons, it will show a list of the parts that are needed for update.