The pulley under the motor is not moving so it is not not moving the blades

Question edited for clarity and all the typos.
Question moved to a better category than 'Garden'.

Surging is normally caused by an air leak. Check from the air filter all the way to the inlet manifold on the cylinder head. When you engage the blades the motor is under 'load'.

More information here, but says, 'not enough fuel or too much air'.

https://www.google.com/search?q=Kohler+7000+22+hp+engine+surging

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moved you from cars to DEERE
when did it last run right , never, last year, last decade or found it dead in a barn , History matters.

there is no tractor forums here, just mowers etc.
is this belt drive or hydastatic drive like see on Cub-Cadet's
Garden tractor it is, not real tractor.(farm)
yes it is hydrostatic
so is this the gear box full of fresh lube oil? spec oil clean.
next is the drive from engine to drive (pulley) spinning?
belt not missing or slipping or shreaded or loose?
make sure controls to hydra box work end to end.
and check pump pressure by the book,"?
the pump is that finned thing on the side. below.
buy the shop manual and it covers trouble shooting.

no sound not even a clicking sound? i would check to see if the fuse is blown and be sure the battery is fully charged if not it wont even click. be sure that there is no grass or rope or sticks caught in the blades or pulleys keeping the engine from turning over.

PDF Manual Web Archive

Customer Service Cub Cadet

when you actuate the "engage blade" lever, two things may occur,
First, a mechanical action, a spring moves to put tension onto the belt.
Second; at the end of its run, actuate a switch (PTF switch) to engage the clutch that moves the pulleys that consequentially move the blades.
if the tensioner is not moving , check if spring has come lose, undone or broken, (more likely in your case) or check the PTF switch.
any other assistance, contact me, good luck.

If you need further help, reach me via phone at https://www.6ya.com/expert/gerardo_79638d1eac6a0a1f

With the model number you have you can search for craftsman parts and go to sears and enter the model number and select the deck and find the replacement belt routing sticker for your deck. It goes on the top, left, front.

The belt comes from the motor pulley in between the pulleys in the middle and around the back of them, then out to the front side of blade pulleys, around the outside and straight across the back from blade pulley to blade pulley. Not a hard routing. If looking down on the deck from the seat it will look like an inverted T. Watch out for the belt keepers that help keep the belt aligned in the pulleys, may need to gently retract them to get belt in the pulley.

How old is your clipper, Oster clippers need to be adjusted for more power and speed, also what clipper blade are you using to cut the horse hair and how long is the horse hair, Also the blade may not be sharp, some new blade are sharp maybe defective.

TO REMOVE THE PULLEY FROM THE CRANKSHAFT END:

Remove the blade belt and, if needed, the deck to give yourself more room to work. Apply your brake pedal and lock it down, this will relieve the tension on the ground drive belt.
If you have an electric blade clutch, find the plug where the wire goes over from the clutch to the frame and unplug it.(Electric clutch will be heavy when unbolted so be ready for it.)
In the center of the pulley or blade clutch you will find a long bolt (most likely a 5/8 head on it) You may need a deep socket to reach it depending upon the type of stack pulley on it, remove this bolt and the pulley should slide freely on the crankshaft. slide it downward and slip off the belt on the top of the pulley then remove the pulley the rest of the way

In my opinion, (which doesn't count for much, I know) the 7hp Kohler Troy Bilt Horse tiller was the best tiller ever made. Those tillers lasted forever if they were taken care of. I've got one of the 8hp Kohler versions, but it's just not the same.

It's become a lot harder to find an engine to replace these engines. You'll most certainly want to go to a Briggs and Stratton dealer and have them look it up. You need a 3/4" crank, 2 7/8" long with a keyway, tapped for a bolt to hold on the pulley and reverse disc. IF you find an engine to fit, you'll likely need to have a custom throttle cable made up to replace the current one. A good small engine dealer should be able to help you.

Now for the bad news. The 7hp Kohler was a cast iron engine. Any replacement engine you find will likely be an aluminum block with a cast iron sleeve and therefore, much lighter. What this means is the balance of the tiller, from front to back, is going to be thrown off. The result is - it will be MUCH harder to pick up the rear of the tiller when you want to turn at the end of the garden. You will most likely need to either put on one of the bumpers (if you can find one to fit) or figure out a way to hang some weight on the engine. I've seen people do some creative things to get the balance back. Whatever you do, it just won't be the same as that great 7hp Kohler. I'd suggest trying to rebuild it - if possible!