Common sources of slow leaks (even when not running)

[Ryban]

I think I have a slow leak somewhere on the raw water side of my engine. There's a small basin beneath my engine and I've been noticing standing sea water here. At first I thought it was a leak caused by the engine running, but after a few short trips, and while sitting there watching the engine while it's running, I didn't notice any obvious dripping.

However, after a few weeks if sitting, the basin has slowly filled with maybe a 0.5-1L of water, and maybe a little oil too -- but mostly water. If there is a small oil leak, I believe it to be independent.

What are common sources of non-running leaks like these, and are there any tricks I can use to help track it down? Clean and dry everything really well, and then look for wet/salty streaks?

[sailor_ed]

I would check for a slow drip from the raw water pump shaft caused by worn seals.

[Stu Jackson]

Originally Posted by Ryban

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However, after a few weeks if sitting, the basin has slowly filled with maybe a 0.5-1L of water, and maybe a little oil too -- but mostly water. If there is a small oil leak, I believe it to be independent. >>>>>>>>>>>>>>>
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Originally Posted by sailor_ed

I would check for a slow drip from the raw water pump shaft caused by worn seals.

Ed's right, I'm off to do just that today on my boat.