As the design details sometimes change, decide if this is the correct thermostat by measuring the outside diameter of the flange rather than by trying to match the appearance.

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)
• M2-12 (Catalina 25, Capri 26)
• M-18 (Catalina 27, Catalina 30)
• M-25 (Catalina 30)
• M-25XP, (Catalina 28, Catalina 30, Catalina 34, Catalina 36)
• M-25XPB (Catalina 28, Catalina 30) through 3/1998
• M-320 (Catalina 27, Catalina 28, Catalina 30)
• M-35 (Catalina 34, Catalina 350, Catalina 36, Catalina 38)
• M-35B (Catalina 34, Catalina 350, Catalina 36) through 3/1998

Outside diameter of flange: 38mm (about 1-1/2")

This part number is only valid for the B series engines with an engine production date up to March of 1998. If your engine was built after that date, order our part Z3355 below in "May we also suggest."