Mariner Throttle Control Issue

[Walleye Wally]

Hi, I have a 1983 80HP Mariner outboard and my controls are a Quicksilver unit. The problem is it accelerates fine, but when I move the throttle back even just a little, the boat slows down so fast that we feel like we're going to go through the windshield. I have tried to find the problem either in the linkage or the motor itself, but I can't seem to find anything wrong. Has anyone else had this same dilema?

Thanks-- Walleye Wally