1971 Johnson 40HP outboards Service Manual, Page 57Get this manual
driveshaft pinion gear rotates constantly with the operation of the motor and drives two bevel gears which revolve freely on the propeller shaftThe ciutch shifter dog is splined to the propeller shaftIn neutral operation, the shifter dog with detent spring and balls is centered between the two gears, which revolve in opposite directions, and remains motionlessIn forward or reverse operation, the shift lever causes the shifter dog to engage either gearPower is then transmitted from the rotating gear, through the shifter dog, to the propeller shaft and propeller REMOVAL OF GEARCASE
Figure 6-5Gearcase Attaching Screws
It is possible to remove the lower gearcase as-
sembly without removing the power head from the llJ.otOrHowever, if disassembly of the exhaust housing is required, it is necessary first to remove the power headSee Section for instructionsThe gearcase assembly may be removed from the exhaust housing and power head as follows:
REMOVAL OF EXHAUST HOUSING, STEERING AND STERN BRACKETS
a Remove power head as described in Section 5