This morning I changed the impeller in my 2002 Merc 250XB and thought everything had gone well until I tried forward and reverse. I removed the lower unit while in forward gear,replaced the impeller and slid the lower unit back into place without any struggle or binding. I was able to start the engine and let it run while hooked up to the hose,run time approximate 20 minutes and everything checked out” OK “. After shutting down I attempted to put in forward gear and it seemed to bind a little,while the shift lever was at the bind point I turned the prop a little, then I was able to push the shift handle the rest of the way forward.This seemed strange to me so I tried reverse and needed to do the same thing to get her all the way into gear. Does anybody have any ideas about what I did wrong or what I need to do to fix? Thanks