1990 Johnson 60 hp tiller kill switch problem

[culli]

I have a Johnson 60 hp tiller and the idle adjustment appears to be worn out because vibration allows it to move and activates the kill switch. I have tried using Teflon tape to take up the slack, but does not seem to help. Sometimes it wont allow the kill button to work until you dial the adjustment in.. I am wondering what I should try to replace, the whole tiller arm, the kill switch and twist grip? or what? Thanks. Culli