Throttle adjustment - very sluggish

[laketravisrat]

Hello! I have a 1989 Evinrude 100 xp that is really slow to respond when I push throttle arm down. I have to push it down parallel or past the top of the boat side panel to even get it to gor forward and more to scoot to plane. Seems excessive. Then, when the motor "catches up" I must back the throttle off a bit to maintain a speed that doesn't over rev the engine. I don't have a manual but am looking for the best price. Can anyone tell me how to get the slack out of the throttle?

Thanks in advance!