1987 sea ray won't engage forward drive

I have a 1987 Sea Ray Seville, with a mercruiser 175 Alpha One I/O and lately the forward won't engage the motor will rev up boat it won't kick in, well actually it will but it takes like ten or more attempts till it finally kicks in and it usually does so in a violent matter. Reverse will engage every time although you can't give it to much throttle or it will die. Just wondering if anybody has any idea what the problem may be and how costly it is to have it repaired.

 

I can take care of it if you are close to Milwaukee.

 

actually I'm at the very Northern part of the state. I'm thinking its the shift cable might be shot, haven't really had alot of time to look at it. Thanks though I appreciate the offer