When you need to overhaul your 15 horsepower Briggs & Stratton motor, you will have to properly remove all the exterior parts from the engine before you can disassemble the main motor. A common attachment on a Briggs & Stratton motor is a pulley of some sort bolted to the base of the crankshaft. The pulleys are used to run belts or chains, but you will need to remove it in order to remove the oil pan and crankshaft later on.
Fit the pipe wrench on the crankshaft of the Briggs & Stratton motor. Hold it firmly so the crankshaft doesn't turn while you unscrew the pulley bolted to the base of the crankshaft.
Fit the proper sized wrench on the bolt holding the pulley to the base of the Briggs & Stratton motors crankshaft.
Loosen and remove the bolt holding the pulley to the crankshaft.
Pull the pulley off. Place the pulley and bolt in a safe location for later reinstallation.