Hi new to this but I would appreciate your help. I have a Honda HR 195...
My concern is the hydro drive which appears as a sealed unit and after 23 years of service I should be perhaps be looking at some sort of servicing i.e changing the oil.
Welcome Mike; I work for American Honda, and can tell you a few things:
1. Here in the USA, Honda's HR195 was never made with a hydrostatic transmission. That said, you probably have a European-spec model, so not sure which style/type of hydrostatic transmission.
2. The hydrostatic transmissions fitted to
all Honda mowers do not require any service, other than checking the level of the hydrostatic fluid. Unless you have a leak, or there is some drive/performance problem, there is no need to drain/fill the fluid.
I understand your concern, but there is no reason to worry. The original HST fluid in the transmission is good for the life of the mower.
You may be familiar with the old saying, "If it ain't broke, don't fix it." That applies to this situation perfectly .