1969 Johnson 4hp shaky throttle

[Evinrudej]

Hi guys I got a 1969 Johnson 4hp I just took it out today and noticed that when at full throttle the throttle sometimes slowly backs it self down to about half throttle so I have to constantly hold it at full throttle. Is there anything I should tighten up or grease to help this issue? Thanks

 

[racerone]

Parts book shows a friction unit on the throttle shaft.----Inside on the lower cowling.

 

[F_R]

Parts 32, 33, 34 comprise the throttle friction assy. Adjustable by tightening or loosening the bolt.
But, as often happens, somebody may have had the coils replaced without adjusting the air gap to the flywheel magnets. If the coils are dragging on the magnets, flywheel rotation will try to turn the throttle to slow or off.