1978 Johnson 4HP outboards Service Manual, Page 81Get this manual
bEngage idler gear with flywheel and lock in position, using OMC Special Tool #383967Place tool in lower motor cover groove along side of idler armTurn thumbscrew provided with tool into hole of idler arm, making sure idler gear is engaged into flywheelTurn flywheel in clockwise direction and wind starterspring into cup and stop assembly until spring loop contacts slot in pulleySee Figure 7-10 1Slot in cup 2Pulley 3Spring
Figure 7-8Spring and Pulley Assembly
dAssemble idler gear with shoulder against idler gear armInstall idler gear arm, and spring to pulley and cupBe sure to position stop on idler gear shaft between the two stops on the cup and stop assemblySee Figure 7-9Avoid turnirig pulley and disengaging end of spring