7. How can I tell the direction of rotation of my prop?

All Atomic-4 engines run in a counter-clockwise (LH) rotation as you would be in front of the engine, facing the flywheel. This means that as you would be facing the prop from behind a boat with a direct drive engine, the prop would be turning in a clockwise (RH) direction.

If your engine has a gear reduction unit installed (either a V-drive, or a standard 2 to 1 gear reduction unit), the prop would turn in the opposite direction (LH).

A V-drive unit is quite easy to identify, since the engine would be installed with the flywheel facing the rear of the boat.

A standard 2 to 1 gear reduction unit would be bolted to the rear of the engine, and the engine would be installed with the flywheel facing the front of the boat. The gear reduction unit has a "bell-shaped" housing that extends approximately 8 inches behind the reversing gear. Gear reduction models of the Atomic-4 can also be identified by the fact that they have four-bolt propeller shaft couplings, instead of the three-bolt couplings used on direct drive engines. - Updated: January 4, 2004