Combines corn head slows down

look for an external leak, if none is there you have a poppet in valve stack leaking. if you ned more info please pass along model of combine as it will help others include specifics........vstk

Need to know model of combine. On my R62 with same problem, there was a relief valve under the left hand side of cab that needed to be replaced.

run the header fast, and unplug the hose. If it still slows down, the relief valve is leaking, if it holds speed when unplugged, then the reel down poppet is leaking.