Ive had a 40 tohatsu for 2 years got it brand new. Ran a ton during covid 3-4 times a week. its happened 3 times now where after running for a while ill try to throttle back, it will either get stuck and won't go click into neutral, or it'll slide in with no tactile click into neutral. When it does go into neutral it'll high rpm to 2k about and come back down slowly its tough when docking and not something I want continuously happening but it runs fine other than that.  First time when I got the boat took it to the mechanic told me it was timing and its as fixed ran Fine for a while, then it happened again took it back they told me it was water in the gas got it back drained tank, ran fine (only ever use ethanol free, as well as kept under a roof not sure how water would get in as well as changing fuel water separator very regularly probably more than most), happened again recently after running perfect for 6 months, took it to a different mechanic and they kept it for 3 weeks worked their butts off on it, adjusted intake valves as well as changing IAC valve. They water tested it and say it was working great and I get it and it does the same thing. 

Any ideas, I'm very frustrated with this I just want it to work. its to the point that when it finally gets fixed I'm getting rid of the boat for something else. Ive read could be thermastat thinking the motors running hot so its idling high to cool off, Ive heard it could be Throttle positioning sensor being bad, and my thought was possibly the throttle control at the helm because I had to change the steering cables recently and thought possibly throttle cable could be bad as well. 

Its under warranty but I didn't really wanna lose it for another 3 weeks in the middle of duck season if its something I can possibly change myself.