The engine saga continues….

Once the Perkins was back together from the rear main seal work and it worked I found a new confidence.  Not a mechanic yet but more aware of how to turn a bolt or two, it was time to open up the heat exchanger.  I was told to have a few dowels ready to gently ream out the holes on the raw water (salt water) side… 

OK first I should explain how this heat exchanger thing works as I understand it.  Sea water (raw water) is sucked through a hole in the bottom of the boat and is run through a strainer to remove big crap that may be sucked in. It then is run through the pump that sucked it this far and will push it to a blue thing (heat exchanger) mounted on the side of the blue engine (Perkins color).  Separately there is also a closed system that is similar to a radiator system in a car that has antifreeze in it.  It pumps green juice through the blue engine and  the blue thing (heat exchanger) on the side of the engine and then back around and around again. There is no radiator in this system. The heat exchanger is in place of the radiator.  It uses the raw water from under the boat to cool the green water, passing it around the heat exchanger and then out to lastly cool the exaust coming from the engine that then flushes the water out of the boat.  This is the spitting you see at the back of almost all boats.

  Once I removed the heat exchanger I found it coated in a calcium like substance and understood why I needed the wood dowels. I attempted to clear out the tubes and soon found that a good boil in a chemical bath at a local radiator shop would be a better solution.   2 days later the guy at the radiator shop told me there was a hole in one or more of the tubes and that he could fix it but it may be better to replace. Holes mean that the raw water and the green water would mix and this is bad.    Replace it I did but as we found  on the Internet the replacement that was recommended is for salt water applications  and the one that I removed was for fresh water.  With Quick shipping and some sweat and a bit of blood  the new one was in and working fine.  Slow Flight spits at a steady stream instead of a random gargle and cough…      


  1. I guess it is best to learn about and replace all of this mechanical stuff before you leave for a foreign land. Bill keeps talking about your leads….Have you checked those?

    1. Zinks anodes are a sacrificial metal that absorbs electricity and melts back to its earthly form instead of the stainless steel, brass or bronze on a boat. And we have replaced all of them. They will need to be replaced in another few months as well. They deteriorate faster in marinas than they will when we are at anchor or on the move.

  2. A trick I learned at just the right time from brother Paul: the alternator quit putting out power in the middle of the night. 5 minutes after he woke me, I was prone on the salon floor, arms extended into the engine compartment with a pair of wrenches. Broken fan belt, but he had zip-tied a spare in place the last time he’d had the alternator (and all the other belt-driven stuff) off. So, loosen the clamps, position the new belt, re-tension, done. Backup belt was one of the best ideas I’ve seen, saved us hours of hassle.

  3. Dude!: Invest a few dollars in Mechanic’s Gloves. They have the grip and dexterity of your hands, but let loose far less blood!

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