i am not to sure what you are geting at? you need to tell us what boat it is ,is it inboard or out board,does it have t/flex or t/flex and power stearing?
I think whats basically happened is that the push/pull cable has worn. Either that or its the helm unit. Its also worth checking that the linkages are free of play. Theres no adjustment in the helm unit if its the rotary type. If you have the rack and pinion, there is a backlash adjustment.
Looking at the age of the boat I'd check the cable. They tend to wear quicker than the other components.