there were two versions of the clutch mechanisms. In both the drive from the gear to the propeller is made through a coil spring. engaging neutral puts the clutch lever in contact with the upturned end of the clutch drive spring keeping it from turning. the spring tends to uncoil reducing tension & allowing it to slip. Lifting the clutch rod allows the long clutch lever spring in the illustration to lift the lever and allow the clutch drive spring to once again grip the clutch drums. The illistration was the version used when the Fleetwin first came out.

It was found that some times the lever would ware into the end of the drive spring and the clutch lever spring would not lift the lever. Sometimes the spring would drop out of position.
Later models but a slot in the clutch lever that engages a groove in the clutch rod giving a more forcefull pull on the clutch lever. You should be able to see the engagement and release ( I used a quarter inch plexiglas disk drilled for the prop shaft and screw holes to steady the prop shaft to adjust the length of the clutch rod.) – top parts page is for later models – bottom parts page is for early models. . . 🙄