I have a troy built tiller oil is Coming from carb while Running.is this normal?

SOURCE: changing the drive belt

remove plastic belt cover
remove the guard,belt/pulley
work in the right side first:
remove the rigth-side wheel
remove the screws of the bumper
remove 2 screws on bracket/transmission assembly
pull the bracket
install the new belt
reinstall the right side screws and wheel

do the same in the left side
Ps: remove the belt guide, and reverse return spring

http://www.partstree.com/parts/?lc=troy_bilt&mn=21A-634K766+7HP+FRT+Roto-Tiller+(2005)&dn=0079200009

SOURCE: how to take motor off frame troy built tiller

The easiest way is to first remove the drive belt , then on both sides you will see two bolts with locking nuts on them where the engagement lever raises the motor to tighten the belt. Back these bolts out , then have someone hold the motor while you work the rod out on each side that the motor slides up and down on. Oh if you have a bumper there are two bolts in the top of each one holding the bumper on to take out first. Hope this helps.

SOURCE: where do i find serial numbers on troy bilt horse tillers

On the old Gardenways Horse the serial number is stamped into the top of a little flange on the side of the transmission just to the right (viewed from behind) of where the handles attach. It may be covered in gunk so a douse of mineral spirits and a little scraping will reveal it.

You can download the manual and parts list from the Troybuilt site. Enter "HORSE" for the model and the serial number.

SOURCE: Troy Bilt Tiller and Pressure Washer

The carbs are plugged. Take the bowl off the carburetor by loosening the nut on the bottom. You'll want to clamp the fuel line before you do this. That nut has a small hole that goes through the nut from side to side, and one that connects them in the center. Use a wire brush to knock all the deposits loose, making sure that the holes are clean and free of obstruction. Put it all back together, and it should run fine.

SOURCE: Changing Drive belt On Troy Built Tiller

You have to remove the engine (4 bolts, no big problem), then remove the bolt in the center of the pulleys, then remove the pulleys. Slip the belt(s) (2 if you have the Super Bronco model) onto the pulleys, re-attach the pulleys with the bolt, re-mount the engine, and you're home free.