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I fixed it!  Yippeeeeeee!

After running aground on Monday I had cleaned out both the stb and port sea strainers.  I still didn’t have good water flow in the exhaust of the stb engine.  I decided to check the impeller, which was good, but unfortunately while pulling it out I damaged it.  I thought I’d have a spare on board, but I did not.  Whoopsi.

For those of you who don’t like to read – go to the bottom and watch the video summary.

I ordered one and had it overnighted to the west marine that I can reach on my bicycle.  $130.00 later I had my new impeller.

I installed it, and still did not have good water flow.  🙁  After talking to a friend of mine who’s an experienced captain he said it sounded like I wasn’t getting a good prime to the water pump.  I looked at the lid to the heat exchanger and decided to seal it super-good using some permatex.  Still no good water flow.

I’m learning that a closed cooling system on a boat has a heat exchanger instead of a radiator like a car.  It uses raw sea water to cool the antifreeze in the engine.  This sea water passes through a tube bundle in the day tank (also known as a heat exchanger).  I must have mucked those tubes up pretty badly.

I pulled the plugs to the front of the day tank (turns out they are supposed to have zincs on them, mine were completely gone).  Another good lesson learned (http://realitycheck.me/checking-and-changing-heat-exchanger-zinc.htm)

The corrosion inside there looks pretty bad so I pulled the side of the day tank off (the one closest to the center of the boat is easy to reach.  Sure enough, it looked like they were completely clogged.  🙁

So, now I had to pull the other side off, I made a board to lie on and crammed myself in front of the starboard engine to finally reach the other side.  It was a total pain in the ass to get that thing off.  Anyway, after doing that I could shine a light on one side and see if I had clear tubes.  Only about 10% of the tubes could I see light through.

I used a coat hanger to clear the tubes, but it left a ton of that gunk in there.  I decided the best way to clear those was to use water pressure.  Unfortunately the weather was cold that day (38 degrees) and so was the water.  I ended up clearing almost all the tubes, and as the water came out it was hitting me in the chest.  I looked like a drowned rat after that was done.  The shirt I had on will never be the same.

That silt material from the bottom of this channel is really gross.  I think it’s like radiator stop-leak combined with crude oil.  Ick.

Finally, after putting the whole thing back together I was completely dismayed to find that I STILL did not have water flow.  Damn.

This morning I decided to try one more time to find the problem.  It must be a priming issue, because everything else has been eliminated.  I decided to try and find an air leak by disconnecting a hose on the upstream side of the water pump and blowing into is (yeah – I put it to my mouth).  I could hear the leak going but couldn’t see it.  I tried spraying windex all over the place (every pipe and fitting) and looking for bubbles, no help.

I took the hose off my shop vac and used it as an extension (and it tasted even worse) I now could hear the air coming out of the top of the sea strainer (the VERY FIRST thing I looked at / fixed).  I had put permatex on that thing but I still had a leak somewhere.  A quick google search revealed that they’re supposed to have a seal (older ones had a cork gasket).

So I made a gasket out of cork and tried it again.  This time it worked, so I decided to prime the system using the shop vac.  It wouldn’t prime!  UGH!  If my shop vac couldn’t prime it that little impeller sure couldn’t either.  I pulled the lid to the strainer off one more time and used vaseline on both sides of the cork gasket this time.  Now – finally – I could get it to prime with my shop vac!  YIPPEE.

I put the whole thing back together and finally have water flow.  Thank God!
Here’s the tube bundle – all clogged up.
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Here’s those infamous missing (used up) zincs.
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This is what my shirt (and my whole body) looked like after flushing the tube bundle
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And here’s the final piece to the puzzle – the cork I made for that sea strainer preventing the water pump from priming.

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Finally – here’s that vid I promised.