Catalina 30 engine

[Antonio Martin]

Catalina 30 1983 engine, I change my engine from 5411 Universal to Universal M25XP, it become with a resser mounted to the engine output, I suppose that the connection goes direct to the water lift, or do I have to do a loop with the hose above the water line then the water lift from the output the water lift I have 2 check valves one is right close to the water lift output and the other the water line then goes down to the exhaust I would like to know how it is the lay out of the hoses of the exhaust and the resser do I have problems with the return of water to engine

[jimbunyard]

Yes, you need a vacuum break above the water line somewhere in the raw water hose.
Not having one risks flooding your engine or even your boat. The typical place for it on a Catalina is just before the raw water injection point on the exhaust riser.

[Stu Jackson]

Engines 101 - The BIGGEST & BEST collection of M25 Series Universal Engine Information on the Internet, plus some M35, too

Diesel Engine - c34.org


There are engine manuals there, too.