Since Bill's site is now gone, I captured these images and texts from an archived copy.
STEP 1: Remove spark plugs and find 28* & 18* (see pic) on belt schroud
Turn fan drive pulley clockwise(much smoother and precise using a crescent wrench) See Pic
If you hear the magneto click in the area shown in the first Pic you are OK.
If you do not hear clicking in this area then proceed to STEP2.
Step2: Remove the top engine schroud
Step3: Remove the spark plug wires from the magneto
Step4: Remove governor and turn engine "clockwise" until you see a "V" on the large gear. STOP at this point.
Step5: Remove magneto from engine. Holding magneto in left hand, rotate magneto drive gear "clockwise" untill you hear a click.
Step6: Insert magneto back into engine (see pic 4) for proper place to insert magneto into large gear.
rotate fan drive pulley clockwise (see first pic) and rotate magneto in engine until magneto "clicks"
YOU HAVE NOW TIMED THE ENGINE!!