1985 Evinrude 40 Hp goes into reverse but will not accelerate

[dlmallory]

I have a 1985 Evinrude 40 HP tiller that everything works great moving forward and in neutral. When i put the engine in reverse the prop engages and spins in reverse. I turn the handle to increase throttle and the engine increases but the propeller doesnt spin any faster. Not sure exactly what is causing this.

I have looked around on here and saw someone mention the shift cable could not be installed correctly. Is that a possibility ? How would I go about fixing it and where should it be installed?

Heres a picture not sure if this helps.