Boat is 96 Donzi 182 Medallion XL 4.3L

Last time we were at the lake the boat would not start when it was time to load up. I thought maybe it was the neutral safety switch, but after checking it out I don't think that was the problem.

I ended up wiggling the throttle control and it started. I noticed it was loose so I tighted up the 4 screws. It had also been not wanting to go to go to neutral without wiggling the control. Tighting it helped with the not going into neutral, but it is still not working as it should.

So today we were at the lake and the up trim stopped working. Turns out to get it to work you must wiggle the throttle control.

What's going on with my throttle control?