I have a 19' SeaRay witha 3.0L Mercruiser/Alpah 1. When I try to shift into forward the boat goes into reverse. I can only get into forward gear if I trim the drive all the way up (trailer) then shift into forward and the gear will engage. I can then trim down and the boat will run fine. Slowing down and shifting into neutral, the boat will eventually shift into reverse. Pressing forward or back on the Shifter will only make me stay in reverse. Then its back to trim up and get into forward gear. Is this just a shift cable adjustment or something wrong with the lower drive. Thanks in advance for the help.