I ask this because I own a mower with the GSV 160 and cannot find any information on it while searching the Internet.
I was allowing a family member to borrow the mower last year, while their's broke. Now that I have it back I want to make sure everything is fine. It is the Hrc216pda, I bought it new in 2012. I use it mostly for the areas my rider can't maneuver.
GCV = Honda's premium residential mower engine. Used in almost all Honda mowers. Has been in production over 20 years, available in 160cc and 190cc versions. Engine block is all-alluminum. The GCV engines use a diagonal split-block design and have both an overhead camshaft (internal timing belt) and overhead valve construction.
GSV = Honda's commercial version of the GCV, the GSV has a cast-iron cylinder sleeve, an extra bearing, 2-stage air cleaner, and a few other minor changes. Honda uses a GSV on some of its commercial-grade mowers, including yours, the HRC216PDA. Same overall design as the GCV, but beefed up in key areas.
GXV = Honda's top-of-the-line commercial engine. It has a cast-iron cylinder sleeve, 2-stage air cleaner, provision for shaft drive, and is of a conventional design with separate cylinder head, engine block, pushrods, timing gear, overhead valve, etc.
If you want complete, illustrated and documented details on both the engine and the rest of the mower, a factory shop manual is the way to go; Honda sells them direct via eBay and Amazon (Free shipping):
Honda Power Equipment Shop Manuals on eBay
Honda Power Equipment Shop Manuals on Amazon