I repowered and older Turf Tiger about 6 years ago, it's hourmeter was still working and was at 3,200 hours. Turf Tigers have horizontal engines and the PTO switch powers the hourmeter, so the engine had more hours on it.
This operator was fortunate as he already had a new engine that he had picked up. Older Turf Tigers had a short engine dimensionally and both Kawasaki and Kohler have discontinued these engines.
Vertical shaft engines generally have a shorter life due to their design, however I don't have any formal proof of this, just hearsay.
Valve adjustments at 400-500 hour intervals appear to prolong engine life.
