We will be using our new TTHP 17 hp Kaw Exmark again today for the 2nd time for about 2 hours.......so it will have about 4 hours on it when we are done. We plan on changing the oil the next time we mow (6 hour mark). The book states to change the oil after 8 hour break-in and I was wondering if it is okay to do it after the 6 hour mark or do we need to wait for the full 8 hour mark? My questions are: do you recommend a certain brand of oil? We checked with the dealer to see if it was permissible for us to change the oil and he said it would not void the warranty if we did it. The warranty book did not mention that the oil filter needed to be changed at this time as well......does that sound right?