motor not revving up in gear

[ub54]

I recently put my sons 50 hp johnson 0n my pontoon .It starts ok but , the shifter seems stiff and the motor will not run faster than an idle . I can open the throttle up by hand and it will rev up . Could I have the cables crossed up ? Because I had to take them off gey it on my boat .

 

[Grub54891]

First, welcome to the forums! Did the cables work before you installed them on your boat? I'd disconnect them from the motor, then have a helper move the shifter, with the neutral button engaged. The cable that moves is the throttle cable.