I have a Walker 2002 with about 700 hours on it. It is a secondary mower, so it only gets 4-8 hrs of use a week. Last Saturday I checked the oil during regular maintenance and found it about 3/4 of a quart low. It had never used oil like this before. I have been mowing in very dusty conditions this spring, so I decided to check the air filter (Donaldson) to clean it. It was very clogged with dust. I also noticed that it had an inner filter. I was told a couple of years back that Walker had recommended removing these filters because they were causing too much restriction of flow, so I thought I had removed them from all my machines. My mower is the model which also has another round kohler ailr filter on the top of the engine. I used the mower a couple of hours this week so far and it doesn't seem to be using oil since I cleaned the filter. Does this make sense? Also, previously I had noticed an oil smell when I turned around and came in contact with exhaust. I didn't get that same smell yesterday when I used it. Could cleaning the air filter make the difference?