This is an industrial centrifugal clutch. It appears to have a 5/8" bore for the shaft and looks like it uses a 5/8" belt. These are used in all sorts of power equipment like lawn mowers, industrial compactors, construction equipment, etc. These are available in different shaft sizes, pulley diameter, belt width and lock up speed. The one in the URL is the most like yours that I can find on-line. The exact use for yours is impossible to determine since there are no identifying marks. The shaft size indicates it's for a gasoline engine. The makers of yours is also unknown.

This is an industrial centrifugal clutch. It appears to have a 5/8" bore for the shaft and looks like it uses a 5/8" belt. These are used in all sorts of power equipment like lawn mowers, industrial compactors, construction equipment, etc. These are available in different shaft sizes, pulley diameter, belt width and lock up speed. The one in the URL is the most like yours that I can find on-line. The exact use for yours is impossible to determine since there are no identifying marks. The shaft size indicates it's for a gasoline engine. The makers of yours is also unknown.

References:

https://www.ebay.com/itm/Centrifugal-Clutch-V-belt-3-4-inch-shaft-Heavy-Duty-...