A friend of mine gave me his old Honda Lawnmower,he said the transmission is bad.Motor good,I was going to put it on another mower ,but I am thinking about Just getting another TX if still available.These mowers are pricey nowdays might be worth it? I havent looked at it yet ,but could be as simple as:
ApplianPar 12 Teeth Drive Gear Kit for Honda HRR216 HRS216 Lawn Mower 12T Pinion Gear 42661-VE2-800 42672-VE2-800 Keys Springs Clips https://a.co/d/dxsG4gF
I never mess with these model belt drive transmission ,If you get older HR215 ,HR214 with shaft drive transmission I can help .Have a 3 speeds and a hydrostatic transmission spare .GX engine are good ,these GCV engine are not worth to save
It may be a simple belt adjustment , open the hood !