How to add friction to this e-bike throttle lever?

hi folks,
this is the throttle from an e-bike – it’s a Hall effect device which normally is spring-loaded. what I want is to be able to pick a setting/level and leave it there and have it stay where I set it. I’ve already pulled the spring out, but what’s left is something really “floppy” that doesn’t have enough friction to stay set. hoping to get some thoughts on how to get the lever to stay where in put it by adding friction somehow. you can see there’s some lubricant in there but I don’t think just wiping it away is going to fix the issue.
thanks!


Maybe an o-ring or some heat shrink?

Maybe a spring washer. If you go this route. I have a set of them. Let me know the size you are needing?

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