Motorguide Digital Tour 82 problem

[skeeter20i]

I have a Motorguide Digital Tour 82lb thrust. When i turn it on at a low speed setting, the blade turns without pressing the momentary button. When i do press the button it goes into hyper drive. Turning the speed up only makes it go faster. I had this same problem a year ago and sent it to get serviced. Now it's back and i can't afford to spend another month w/o a trolling motor. Is there perhaps an easy fix to this?

Thanks