Small Engines (Lawn Mowers, etc.): Honda GX 200 6.5 HP, small engine warehouse, honda gx 200

Question
I just purchased this engine from Small Engine Warehouse. They advertised it as a replacement engnine for the Troy Bilt Horse model.  I mounted this engine on a 1974 Troy Bilt Horse model. No trouble during the installation.  Added fresh gasoline and 30 weight oil. Started right up.  Runs fine until I start to use it for tilling.  When using the tiller if the tines hit a rock or extra hard soil it tends to stop suddenly.  Also when I'm tilling in smooth soil, if I raise the depth bar so the tiller can till to the maximum depth the tiller will stop.  Appreciate any help. Thank you,  

Answer
 Hello Ray:

 Turn the Carburator High RPM Air Mixture Screw Counter Clockwise 1/4 Turn. The Air Mixture is too Lean for for the Engine to Operate Properly under a Load. Send me the Model Numbers Off of the Engine, Please. With these Numbers I can Locate a Breakdown for you to View Online. Hope this Helps. I am here if you Require more Assistance. Let me know what Happens, Please. I enjoy knowing the Outcome. Thanks.

 Good Luck

 Respectfully

 John