Yanmar 3GM30F Anti Siphon Valve Raw Water Discharge

Oct 10, 2017
21
Hunter 41DS Westport Marina
I have a connection on the raw water discharge from the heat exchanger outlet to the exhaust and it appears to be some kind of anti siphon valve. It is leaking slightly during running of the engine. Is this normal or is the valve shot? Thanks - Geoff
 
Jan 30, 2012
1,123
Nor'Sea 27 "Kiwanda" Portland/ Anacortes
An important device. It opens and stops seawater from siphoning into the mixing elbow. This prevents exhaust discharge hoses from overfilling and back flooding into the motor exhaust valves (very destructive) when the motor is off. Chances are the diaphragm in the little valve (at the top of the loop) is open slightly because of salt water accumulations thus it leaks when the motor is on. Remove, clean, reinstall - otherwise replace.

Charles
 
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