Small Engines (Lawn Mowers, etc.): Mower dies when blade engaged, proper manuals, carburetor

Question
I came across a John Deere 21" 3.5HP push lawn mower Model FO22B, at a yard sale.  I can start the engine with the blade not engaged.  When I engage the it stops.  

I have inspected the blade clutch and the plates are moving when the leaver is opened/closed.  When I spin the blade, it will spin a couple of time with no resistance, then it will develop a considerable amount of resistance.  I can push it through the resistance but have to use considerable force.  Then the blade will spin with little force until it reaches that point of resistance.


Again the motor runs fine when the blade is not engaged.

Any suggestions?

Answer
Hello Cecil:

Send me All the Numbers Off the Mower and the Engine, Please. With these I can Locate the Proper Manuals and Better Assist you. However, from your Description, it Sounds like the Carburetor is Out of Adjustment. With the Model Numbers I can Tell if there Are Adjustments on this Carburetor. The Resistance you Feel May be the Clutch Grabbing. Does the Blade Bolt Stay Centered or Does it Wobble Up and Down or Side to Side? If Yes the Crankshaft or Clutch May be Bent and Require Replacing if it is the Clutch and Replacing or Straightening if the Crankshaft. The Carburetor May Be Either too Lean for the Extra Load the Blades Add to the Carburetor or the Carburetor Needs to be Removed, Disassembled and Soaked Overnight in Carburetor Cleaner(I use Gunk). Then Blow Out the Passages with Compressed Air and Install New Kit. Hope this Helps. I am here if you Require more Assistance. Let me know what Happens, Please. Thanks.

Good Luck

Respectfully

John