Helper was out discing today and noticed the 8760 started struggling.  He had to drop a couple gears to finish the last couple rounds of the field.  Was struggling enough he couldn’t do road gear home.   He checked air cleaner recently.   He has commented recently it doesn’t run warm but not as cool as it he felt it should.   Listening to it idle it we both agree it sounds fine.   He also thought he might of felt a slight vibration with his feet on his drive home and while standing behind it unhooking the disc we both heard a whine.  First thought is to change fuel filters.  Any other ideas?   Thinking we may have two separate problems.  He’s a good conscientious operator that is mechanically inclined and has spent more time driving it than I have.