yanmar 1GM10 - cooling problem? (Hunter Ranger 265)

[fjweaver]

I serviced the engine at the weekend, I replaced the impellor & engine anode so had to drain the water system.

Yesterday I took the boat for a good run and there was plenty of water coming out of the stern scupper.
On the port side by the cockpit locker just below the rubbing strake there's a small outlet that a fairly steady stream of water usually comes out but I noticed yesterday that there was barely any.

I can't find reference to it in any manuals. Have I done something wrong? I'm sure the impellor was replaced correctly but i did tighten the speedseal fairly tight (after an initial leak)

Would be grateful to know what this is and what I can do to rectify it

thanks
Frank

 

[rob2]

It sounds like the outlet from the anti syphon valve. There are two types, one has a valve that seals when there is flow, the other simply allows some of the flow to divert to a secondary outlet. As it seems there is no actual valve in your swanneck, the most common cause - valve stuck and requiring cleaning does not apply. It may be that there is a salt accumulation blocking the pipe, however. Look for the take off point at the highest point of the water feed and clean it up (internally). the lack of flow will not endanger the engine through overheating - you've established that there is cooling water flow already. The risk is of the water syphoning into the exhaust with the engine stopped. This water can be ingested through the exhaust valves and cause bent conrods!

I may be wrong, of course. Engines have a habit of throwing up misleading symptoms - but check it out?

Rob.