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.
And here’s the final piece to the puzzle – the cork I made for that sea strainer preventing the water pump from priming.
Finally – here’s that vid I promised.