Honda BF35A-BF45A Outboard Motors Shop Manual., Page 115Get this manual
VALVE SEAT WIDTH STANDARD SERVICE LIMIT
1.25- 1.55 rnrn
(0.049-0.061 in)
2 rnrn (0.08 in)
5) Make light pass with cutter remove any possible
burrs at the edges of the seat
61 After resurfacing the seats, inspect for even valve seating,
Apply Prussian Blue compound or erasable felt-tipped marker ink to the valve facesInsert the valves, and then lift them and snap them closed against their seats several timesBe sure the valve does not rotate on the seatThe seating surface, as shown by the transferee! marking compound, should have good contact all the way around