My Dad has a Cub Cadet Tractor with a 20 H.P. Kohler Engine that has an oil filter on it.
At 25 hours I changed the oil and added an ounce of auto-rx, at 50 hours I changed the oil again and it was a little bit darker from the previous oil change.
Yesterday at 75 hours I changed the oil again which had an ounce of auto-rx and the oil was a very dark brown color. I have saved the oil in a clear can and if anyone wants me to do this I can post some pictures soon.
