I have a 1991 Force Outboard, 120 hp. I am having issues with the reverse on the engine. First let me start off by saying that the clutch dog and reverse gears have all been either replaced or inspected. The engine will not shift into reverse when started, it will sound like the gears are grinding and not catching. Once the engine is ran a little while, warmed up as I say, the engine will go into reverse with no problem. Is there something where the lower unit could not be adjusted properly and once the engine warms up a piece fits into place? The linkage has been inspected, looks good, and we have alinged it to the best we can. Any ideas or thoughts?