Is this the old 70's/80's vintage Crown? If so, it is a really simple reel that not a whole lot can go wrong with. When you put the spool back on, are you getting the click when the spool seats itself on the shaft? If not, the spool is going to come off pretty much every time you tip the reel upside down. If it isn't seating, take a small screwdriver and open the click mechanism on the spool face. Clean it out real good with a solvent, put some regular reel oil on it and put it back together. See if this works. You might have some grit or grunge that is keeping the thing from allowing the spool to seat. If this doesn't work the thing might be shot and its time to get another reel. The Crown was a good, basic reel. I've been using mine as a backup reel for my smallmouth outfit for over 20 years without problem. Good Luck!