Hard on Throttle

[seaseville16]

For me its a hard to explain but i will try and see if there is somebody familiar with my problem.

My object is a Searay 16 from -89.
I have recently bought and did some minor reparations and are now ready to get seaborne.

The boat is equipped with an outborder 100hp Searay two stroke from 1989 boat and engine performs very well.

My problem is the throttle when i slow down its kinda all or nothing, not smoth at all so when we have speed regulations in the harbour i have to work a lot up and down to get right speed.

So now i wonder could i do something to make the throttle linkage work smoth or....

Thanks
michael