All, There was a question on a previous thread I posted regarding the 'recommended' service intervals for the Bad Boy ZT60 with the 27 hp Kohler engine. As I stated before, the owner of the dealership where we bought the BB said the first oil change should occur between 8 and 10 hours. His son, who delivered the mower, said the first oil change should occur by 5 hours. I don't remember when they said to do the first hydraulic oil and filter change. The question from the readers of the thread was: "What does the owner's manual say?" OK, there are two owners manuals for the engine, and one manual for the mower (hydraulic system). Kohler Courage Pro engine manual: Annually or Every 100 Hours: Change oil and filter. (More frequently under severe conditions.) Bad Boy ZT Model Owner's and Service Manual: Oil Change: Within FIRST five hours of usage, change engine oil and filter EVERY 50 HOURS OF USAGE: Change engine oil and filters EVERY 250 HOURS OF USAGE: Change Hydraulic Fluid and Filters Humm, Bad Boy is a lot more conservative on their maintenance requirements. For us, every 50 hours will not be a problem. Regards, Joe T.