Rotational weight is the weight of objects that are spinning, like the flywheel or propeller. It's a measure of inertia, or how easy or difficult it is to start rotating a body or to stop it.
 
Our precision CNC lightweight Aluminum Thrust Washer reduces rotational weight by up to 83%  (69g vs 413g) when compared with stock steel or brass washers.

Fits all Mercury "small" one-inch shafts and lower units including XR6, CLE, Torque Master, Sportmaster, 135, 150, 175, 200, 225 hp, 260 ROS, 280, 300 Drag, 2.0 Liter, 2.4 Liter, 2.5L, 3.0L as well as Alpha I, Gen II, and Bravo I drives.
 
Part Number
13171, 18-4220, 21300, 77987, 77987A1, 835467, 835467Q01, 8354671, 12-835467Q01
 
Includes one (1) CNC lightweight Aluminum Thrust Washer (weights around 69 grams vs 413 grams)
 
Contact Mike Hill at STVracer@yahoo.com