yamaha 90hp 1980's fuel problem

[vtmignogna77]

my dad was on the river yesterday and according to him, our motor was "chugging" as he pushed the throttle down. When he came home, it ran like a champ. I was told this is some type of fuel problem? any help is greatly appreciated.
Thanks, Evan

[jb123]

analog or digital gauges ?
does buzzer work correctly ?

[99yam40]

Sounds like a carb cleaning is needed, but not too much to go on