The shift interrupt switch can be tricky to adjust as there is very little movement required to get it out of spec. The manual gives specific instructions on how to adjust it. As regards cable adjustment you have to find the mid point of the cable when shifting. This is referred to lost
motion which is nothing more than the slack in the cable when shifting from forward to reverse. If your outdrives are the cone clutch
type it is often the shift fork that is at fault. When set up correctly these units tend to be trouble free.