This filter is the factory replacement filter used inside of the fuel lift pump in every Universal engine installation we are aware of. It is the factory part #300128.
You may not even be aware this filter exists. It resides inside the fuel pump and is accessed by removing the bottom cap of the pump.
Applications include these engines (and the boats that we are aware used these engines... There could be other combinations as well):
• M-12 (Catalina 25, Capri 26)
• M-2-12 (Catalina 25)
• M-18 (Catalina 27, Catalina 30)
• M-25 (Catalina 30)
• M-25XP (Catalina 28, Catalina 30, Catalina 34, Catalina 36)
• M-320 (Catalina 27, Catalina 28, Catalina 30)
• M-35 (Catalina 34, Catalina 350, Catalina 36, Catalina 38)
• 5424 (Catalina 38)
• M-50 (Catalina 42)
If you happen to drop the filter while removing the old one and are wondering how to install the new one, insert the small end of the filter (with the smaller i.d. but more red plastic) first. The end with the larger i.d but less red plastic should be at the bottom, just above the bottom cap.