I can shift into reverse and it works fine. however, when i try to shift into forward the gear never engages and the throttle increases like neutral. the linkage used to be tight but i made some adjustments and it workeed fine for a couple of years. i have disconnected the lower cable and the lever or throttle moves freely in both forward and reverse. if i pull on the lower cable reverse engages and prop stops turning. when i push lower cable all the way in the prop spins freely. the adjustment of the lower cable is screwed all the way in meaning i have no more adjustments. does anyone have any ideas or other checks i can do??? 