I have a grasshopper 722D mower that dies when on side slope with discharge chute on uphill side. Both fuel filters have been replaced by dealer with Kabota filters, but the problem has not been fixed

Turn the mower off and allow it to come to a complete stop or unplug it. Make sure the internal rear deflector is in place by lifting the rear door. Otherwise, the grass may get caught in the rear opening and cause the mower to malfunction.
Lift the door on the side of the mower. Look for the hooks on the underside of the door.
Line up the hooks on the door with the slots on the side discharge chute. Lower the door onto the chute. Grass clippings will now exit through the chute during operation. To remove the chute, reverse this process.

The float in the carburetor might not be floating at the right height due to the slope. It's also possible fuel might not be reaching the carburetor as it hates to flow uphill. It's unlikely it has a fuel pump. Hopefully, it has an oil pump (and associated oil filter). Engines without oil pumps don't like inclines very well.

If you need further help, I’m available over the phone at https://www.6ya.com/expert/david_29ad5d1dd86564b0

Check the gas level.

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I have provided a link on how to change the discharge chute on a walk behind lawn mower. It is usually pretty straightforward across manufacturers so it should be of help to you.
But in quick terms, you lift the chute cover that holds it in place, remove your current deflector, and insert a new one! It's easy!

Best of luck!

How to Replace the Discharge Chute on Toro Walk Behind Lawn Mower

There are 2 bolts with nuts that mount the spring/door assembly to the mower deck.

Check the float level in the carby. It should be parallel to the body of the carby when held up lightly with your finger tip(after removing the bowl off the carby). If not replace the fuel needle.

Side discharge chute, Side chute, Discharge chute...just to name a few.

it could be a low lift blade on it. try to get gator blade for mulching..... or a high lift blade. lol, size does matter!!! this may fix the issue. there is so many blades out there now, experiment till you find what your looking 4......

I owned the same model, quite simple wiring. I went to the local Grasshopper Dealer and cross referenced it with the Grasshopper model 1212. (which is the same model because grasshopper made all of Wood's mowers for quite some time) I asked them politely and they printed it off for me for free and then I made a few purchases (oil filter, air filter, etc) because I didn't want to seem like a cheap skate.

Hi, Suggest, if you have not already done this, replace the fuel filter.