Any help would be great

I have an older motorguide trolling motor and i have know idea if this is normal or not. When i'm fishing and have the motor switch in the on position and on any speed, as soon as i let my foot off the pedal it swings to one way making the boat go into a slow spin. So i have to have it so when i take my foot off the pedal it stops . I know the new ones hold there position the guy at the store said i likely have something wrong inside, and that i should be able to take my foot off the pedal and it should keep it direction.

Any suggestions would be great. I have know idea how old the motor is but say at least 5 years old.

Thank guys and Happy Holidays