Leaking seacock

[Trekka]

The raw water intake seacock on my boat is leaking. When I have the lever in the closed position and take off the spinloc water pump cover, water comes gurgling out. I can open the seacock a bit and see the flow increase, but moving the lever back only decreases the flow - does not end it.

I tried moving the lever in small increments on each side of the minimal flow position. But I cannot get it to stop completely. I have tightened the valve to the point that I need a rubber mallet to move the handle, but no change in the flow. I serviced and greased all the seacocks a year ago. this problem seems new. But maybe it is not.

Any ideas why the valve does not shut off completely? This is a big, bronze 1.5 inch or bigger valve, probably a WC.

[SilentOption]

Stupid question but.... Are you sure the water is coming from the valve and not draining back down from the engine.

Have you removed the hose at the valve and done the same test?

Is there an Elbow on the valve or a straight fitting? If its a straight barbed fitting you should be able to see the ball inside the valve and possibly see if its scarred. Assuming water is still coming in.

There would be some risk involved but you could get under the boat and put a DC plug in the through hull then cycle the valve open and closed and look for debris or damage. The risk part would be attempting to remove the valve. Not sure I would do that or you would want to but maybe.

If its been on a long time you could break the through hull seal.

[Evan]

If it's a tapered plug type, they do get worn and can leak. By "serviced" did you take it apart and inspect the plug? Did you lap it with valve grinding paste?

[migot1]

You can plug a wooden wedge from outside-diving to the intaake-for the time beeing. but then you have to get the boat out of the water, and have it fixed.

[Trekka]

The seacock has an elbow. I took pictures of all the seacocks and parts when I disassembled them, cleaned, then reassembled. My pictures of that plug show no obvious pitting. To be fair, by "service" it means I disassembled, cleaned (case, inside, plug) lubed and reassembled.

Re: possible draining back from engine. I think this is not indicated given I can increase or decrease the flow by moving the handle on the seacock. If the valve closed fully the water draining back from the engine should not be affected, and certainly not keep on running for 15-20 mins.

[Weyalan]

Seacock valves are not particularly expensive, nor particularly difficult to change.... just sayin'