FC's are no longer produced AFAIK.
If you describe your problem, I'm sure some of us on here could help you out.
The main things in repowering equipment is
1. Crankshaft Length
2.Crankshaft Diameter
3. Horsepower/ dont go any less than what was originally on it, Being a 150cc, its probably a 5.5hp.
If you contact Kawasaki Engines with that model number, they should be able to give you the crank length and diameter,
Or, go to here
http://www.smallenginewarehouse.com/
and click on 'Repower Old equipment' scroll down to snapper, and you'll find the model number of the snapper mower.