I just had the fuel shut off replaced and worked great. Now it starts and idles fine. But when you go and give it fuel it sputters and will not move. If you put it in neutral and rev it up until it clears it will run fine. Its a 97 KQ300

 

Check the pilot jet. You could have dislodged a piece of dirt somewheres that went into the carburetor. Compressed air should be able to blow any crud right out. It does not take much, and if you haven't added an inline filter, good time for one. Might even want to replace fuel lines if they weren't already done.