Try Graphite...........
Cate, Try using abit of graphite (powder of liquid) and squirt on key or into key hole. If that does not work, the tumblers are worn or you have th wrong kewy and it would be best to replace the ignition switch. I have the M-18 on my Catalina 30 and we both probably have the same panel or close to it. Its quite simple to remove the panel, pull back and remove the ignition switch. Map out the wiring before removing from the panel. Tape the wire ends to avoid any contact. All the marina parts stores carry stock ignition switches, so match number of contact points and re-install (10-minutes). You have a new switch, and no worry about having to "jump wire" or being without power. With the panel out, I even replaced the "push button" start switch as well. Simple, and not expensive replacements. Good luck. 30 Catalina
