1979 Johnson 235hp Throttle very stiff

[Hooked on Catfish]

I took the boat out yesterday for the first time since I bought it. It started up fine and idle excellent. My problem is the throtle is very stiff. It goes into gear forward and reverse but very little increase in speed and it is hard to push throttle.It has the Johnson Comand Center Controls. Any ideas where to start? Thanks

[boobie]

Disconnect the shift and throttle cables from the mtr and try it. If it still works hard you could have bad cables or binding in the control box. If they work free you have a mtr prob.