Hesston 9260

[Atlasdiesel802]

Hesston 9260 mower, never worked on them but customer has one that will occasionally slow down cutterbar speed but itself. It’ll run fine and cut grass at 2500-2600 rpm on the cutterbar and then randomly slow to 2000 or 1500. Turning the speed dial to zero then back to full speed will usually bring it back up. Speed sensors are ok, dial has been replaced. Anybody seen this issue?

 

[used red MN]

Hello Atlas, welcome to YT! I know nothing about the repair of those particular machines. From a web search it looks like the cutter bar speed controller may produce codes to diagnose problems with it see the linked post from another forum. New AgTalk post on 9260
Sounds to me like you will need a repair manual to sort this out. It also seems like repair manuals for that machine command a fairly good chunk of change.

 

[Brendon-KS]

I would suggest tapping a hose into the charge gauge port on the header drive pump and running it up to a gauge that you can view from the cab so you can monitor the charge pressure during operation. A loss of charge pressure will cause the pump to destroke with a corresponding header speed loss. Another possibility is a faulty electronic displacement control (EDC) unit on the pump. Although technically it could be the controller mounted in the cab this is typically not the case - solid state devices tend to be pretty reliable, especially when in a protected environment.

It's a Danfoss Series 90 pump and technical information is available on the Danfoss website.

 

[Brendon-KS]

A little more information . . .

The header speed controller in the cab has four indicator lights - power, system, mode, and status. The power and system lights should be on with ignition power and indicate that the system is healthy. The status light will only come on with a fault and will flash in a sequence of four flashes, long and short, to indicate a fault. There are a total of five fault codes that have unique flash sequences. If the status lamp isn't flashing when the header slows down you'd be looking at a hydraulic or mechanical issue, not electrical.