Re: [EXTERNAL] [C400] Impeller Change

Stefan Damstrom

I watched a YouTube channel today on using Barnacle Buster (1:4) with fresh water and routing the raw water hoses to a small bilge pump in a bucket with this solution.  By running this for an hour, the mild acidic solution was able to clean the heat exchanger and I water, it would likely make it easier to remove in the future. 


Agree Ken that it should be a regular maintenance item including making sure each of the tubes is clear.




From: Ken
Sent: Monday, June 28, 2021 3:28 PM
Subject: Re: [EXTERNAL] [C400] Impeller Change


Since Nick raised the subject of avoiding removing the end caps on the heat exchanger as a bonus, allow me to be a Debbie Downer for a moment.  I'm a firm believer in removing the Yanmar end caps every 2 years when you change coolant.  That heat exchanger end cap assembly was installed dry, meaning no galvanic protection paste was applied to any of the parts. Warm sea water, copper, aluminum, bronze, nickel and steel are in that mix.  In this forum I've read a few times how hard it was to remove the tube stack, had to use a hammer and a block of wood to remove...your periodic maintenance is lacking.  That tube stack should slide right out.  But typically the aluminum casting on the end of the heat exchanger is the first to go.  Here's an article on the subject from Tony Athens, a Cat diesel guru, but the concept and materials of construction are the same.


Catalina 400 MKii #190
Bellevue, WA 

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