1971 Johnson 40HP outboards Service Manual, Page 23Get this manual
CARBURETOR AD.lUSTMENTS THROTTLE CAM ADJUSTMENT aIf throttle does not close, either the throttle return spring is too weak and should be replaced, or the throttle or linkage is bindingbTo check throttle adjustment, advance throttle control so that mark on throttle cam is in line with projection on intake manifold See Figure 3-19 At this point, the throttle valve should be closed, the cam follower roller must touch camIf not, adjust as follows: cAdvance throttle control until mark on armature plate cam is in line with raised projection on carburetor manifoldSee Figure 3-19d Loosen throttle arm clamp screwMake sure that throttle valve is in closed pOSitionthe cam follower roller must touch cam, and tighten screwSee Figure 3-20eThrottle valve should just begin to open after mark on cam passes projection on intake manifold as throttle is advancedfTo adjust throttle to conserve fu el at ruising speed, move armature base by hand full spark advance, without touching throttle controlAdjust control rod collar for 1 32 inch clearance from pivot pinSee insert, Figure 3-20