How'd that get wet?

[SurryMark]

My YSB8 ran swell when I dropped anchor and charged the batteries, and the next morning it made awful noises and wouldn't go. Turns out that inside the starting motor was all wet (with a slurry of ancient graphite), and it might have been wet for a long time, because parts were pitted. It didn't show signs of rust until it was dried in the sun and with a torch. It's being fixed now, but my question is, wha happen? Has anybody seen such a thing? There is no sign at all of high water in the boat, in fact the engine is exceptionally clean for its age. The engine always started with the barest touch of the key. Could it have had water inside for 30+ years? The alternator-starting motor guy said "old Yanmar boat engine?" the moment I walked in the door with the starter, and he said he's never seen anything like it.

[Oswego John]

My guess.

Worn graphite brushes. Heat was generated from high loads then condensation caused moisture. Other than that, I haven't a clue.

O J

[Klem]

Is there any chance that you had a water leak above the engine? A common culprit is a bilge pump line that leaks a tiny bit, they tend to be salt water which adds to it.

All it takes is for the starter to be immersed once and then not properly cleaned out and it will keep rusting.

[sgbernd]

The water had to come from either the engine or a nearby leak.

Taste the water and see if you can tell if it is salty or fresh. If salty, there may be a leak from the engine (like water pump, gasket, hole in cooling line, leak in mixing elbow, etc.) which is finding its way into the starter. Unfortunately, you will only find it while the engine is running and the water pressure is up.

On my boat, when under power, a small trickle of water is forced up the rudder post and runs out the cockpit drains. I could imagine something similar, except the stream finding a less innocent path. Again, you will only see it with the engine running at near full load.

If water is coming thru the fibreglass core, it will taste acidic (awful!) and leave a foul sticky brown residue where it evapourates, leaving the rotted balsa and resin residue. Sometimes, when bad enough, you can find little brown sticky stalagtites where it has emerged from the core. Look for these over the engine along the bottom of the cockpit sole.

If the water leak is fresh, you could also have a plumbing problem. Sink plumbing, fresh water plumbing, etc. This should be fairly easy to find if it is the source.

Good luck.

[SurryMark]

It's a Click And Clack conundrum, and I'll post an answer if something clear emerges. Meanwhile, I'll see if a bilge pump line goes overhead, and I'll watch carefully when it's running (being optimistic). Taste it? Guys - you should have seen that mess.

[Kevin Kaldenbach]

Big heavy chunks of metal like bell housings blocks and starters collect moisture from condensate. Moisture and dissimilar metals in the starter breed corrosion