Valve Contact Area Check

1. Check seat location by coating face of freshly refaced valve with Prussian Blue and set valve in place. With light pressure on valve head, turn valve one-quarter turn and remove.
2. Wipe Prussian Blue from valve and put it back in place.
3. With light pressure on valve, turn it one-quarter turn and remove. Do not touch valve face when removing. Look at valve face. There should be a line of blue about one-third of the way down face from margin, all the way around valve face.
4. If line is not in proper position reface valve seat.
5. Check valve seat width.