SSMs & SSM3A's
 

Anyone know what the difference between the 3 and 3A's are?

I got this from the Mercury's web site hope this helps.


The III-A Super Speed Master (SSM) drive is a veteran of Mercury Racing drive stable. An updated version of the Mercury Racing III SSM drive, the III-A SSM drive features larger vertical bearings in the upper housing. The larger bearings provide increased rigidity for the driven gear, resulting in increased bearing capacity and longer life. Larger driveshaft splines provide greater strength, while larger pinion bearings hold lower bevel gears more rigidly, resulting in increased bearing life. A larger propeller shaft increases drive strength and is rear loading for improved shaft contact with the propeller. An extended “nose” on the gearcase improves water flow and boat handling.