I recognise the air cleaner, and I should have recognised the top cowl (which is the only one on a pushrod Honda that is integral with the fuel tank), it is my favourite Honda mower engine. It is 140 cc (actually 135, but who's counting?), 5 hp, and a particularly lightweight engine for a Honda. The mower is most likely an HRU195, assuming it is 19" cut - it doesn't look like a 21" cut, which would be an HRU215.
There is a black spot on the top of the deck near the left front wheel which might be a stone-hole. You should also check for a crack in the base near the left rear wheel, right at the bottom of the vertical part where it meets the horizontal part. While you are at it, look for a vertical fatigue crack on the left midway between the front and rear wheels. Those are all sometimes found on ex-contractor Hondas with that base, whether they have the 4 hp (GXV120), 5 hp (GXV140) or 5.5 hp (GXV160) engine. So far as pleasability, quiet running, and light weight are concerned, the one you have is the pick of the bunch. My own favourite Honda has the GXV120, because the GXV140 has a plastic camshaft unless you have the self-propelled version, but I've personally never seen a worn out plastic camshaft on a Honda. Nevertheless heavy-handed repairers have been known to destroy the plastic timing gear, so I tend to look askance at ex-contractor GXV140s. If it hasn't been butchered along the way, though, it is the one I'd choose.
If it is free of the defects I mentioned, that should be an exceptionally good mower. My HRU195 is a pleasure to use, even though I prefer my 30 year old HR194 in the summer, just because it is a classic and an almost indestructible mower. As you'll gather from my warnings about cracks in the base, the HRU bases are rather tender by comparison.
