This is a Johnson antique outboard motor P50-P70 rotary valve assembly.  This has the fiber drive gear. The steel gear was only originally found on the PR racing versions.  Fits the 1930 to 1934 2 cylinder models P-50 to 1934 P-70.  These engines all have a 1/2 speed rotary valve that sometimes burned up the bearings. In 1929 they used a full speed rotary.  This is not an easy part to find in any condition.  Look at the photos and email with questions.  Thanks for looking.