1988 Yamaha 175 screaming idle at startup

[souwester1985]

I have a 1988 Yamaha 175 precision blend outboard. After arriving at my fishing spot last week I noticed that I could not shift into neutral. It would idle down to around 1000 rpms and then felt resistance. I forced it into neutral and then the engine started screaming at max rpms. Turned it off quickly, cranked it back up, and instantly screams to max rpms again. Got towed back in, and after inspection the cables look intact and will move the shifter arm and throttle arm. Inside the binnacle control cables look fine as well. Any thoughts of where to go from here? Thanks

 

[99yam40]

I would be looking at the throttle plates and linkage to see if they are not closing back to idle position,
and look to see if the timing linkage and plate it loose or stuck a WOT timing