2009 Yamaha F40 Outboard Service Manual, Page 184Get this manual
Power unit (check and adjustment)
Adjusting the valve clearance
Adjust the valve clearances when the engine is coldDo not turn the flywheel magnet counterclockwiseOtherwise, the water pump impeller may be damaged1Loosen the valve adjusting locknut a, and then turn the adjusting screw until the specified valve clearance is obtained
4Install the clamps to the cylinder head cover d5Install the ignition coils e, and then connect the ignition coil couplers d6Install all the spark plug caps f7Install the fuel filter assembly g, the fuel hoses h, and the blowby hose i