Re: Removing trim/transom assembly?? 89 Force 125
you don't need to replace your transom or swivel brackets unless there is some other reason.
The oildyne system pictured is a drop-in exchange. take off the three pump bolts and remove the lower shaft. Oildyne unti will fall off transom brackets. take out same three bolts, lower shaft, upper shaft and your prestolite system will similarly fall off existing engine.
By the way- hang onto your old prestolite pump and oil tubes. when that oildyne goes out it will cost you more to repair it than throw away. the prestolite pump can be made like new for under $200.