The best way to determine the proper rotation (direction) of the compressor is to view the directional arrow imprinted on the belt wheel of the compressor pump.
The belt wheel is the larger of the two "pulleys" on the compressor and it has curved spokes designed to draw cooling air across the pump as it turns.
To check the rotation, stand behind the compressor and look closely at the belt wheel through the metal belt guard.
On one of the belt wheel spokes there is an arrow molded into the metal-cast part indicating the direction which the belt wheel should rotate during normal operation.
Here is an example of the arrow on the belt wheel:
This applies to electric and gas driven models, including: SS3, SS5, TS4, TS5, 2340, 2475, 2545, and 7100.