Dwight,
I have an M35B (which is a newer engine but appears similar to the M4-30) in Imzadi, and my process for cleaning the heat exchanger is slightly different than Chuck’s but accomplishes the same thing. My heat exchanger is athwart the aft end of the engine. Access to the heat exchanger is only practical through the cockpit locker on the starboard side. Both cleaning the exchanger and changing the pencil zinc are done from down in that locker. The end cap of the exchanger on the port side of the boat is almost impossible without major surgery because of the quarter berth. Shut off the raw water seacock. Remove the end cap and seal to open up the chamber that includes the zinc and access to the cooling tubes for the raw water. As with Chuck’s exchanger there are something like 30 tubes that run through the body of the exchanger that holds the fresh water. You will lose a gallon or two of raw water into the bilge, but you are not opening up the fresh water side of the system at all. I use a rod and stiff wire brush, that I bought at the local sporting goods store for about $20US, that is made for cleaning the barrel of a .22 caliber rifle. The brush will clean the scale from inside the tubes very well. I have also pushed a couple of chunks of corroded zinc out of the tubes when I went more than a year without changing the pencil zinc and the zinc was really used up. Push the rod and brush through each tube and then pull it back out. Reassemble the end cap, turn on the seacock, and you are good to go. The hardest part is cleaning and repacking the locker and climbing in an out. I personally think every boat should come with its own midget, or with a precocious 12 year old that has a mechanical engineering degree. My boat normally runs about 165-170 degrees, and will get to 185 or so if I push it at hull speed for a while. Two years ago I had experience with it climbing above 200 (which is why I got the tool for cleaning the heat exchanger) but the final solution to the problem was replacing the pressure cap on the fresh water side of the engine. Be sure to check out the cap, thermostat, and hose clamps on the fresh water side if you have not done so already. At the recommendation of my friend, who is a diesel mechanic and helped with my repower 5 years ago, I change the zinc yearly and clean the exchanger every two or three years. He recommended doing it every other year if sailing in salt water to avoid salt buildup. He indicated there is really no need to clean the fresh water side of the heat exchanger if you keep proper coolant in the engine. Because there have been so many stories on the list about plugged exhaust elbows on Yanmar engines, I asked about the need for cleaning the exhaust riser on my Universal. He said the Universal/Westerbeke/Beta engines are quite different than the elbows on the Yanmars, and very seldom have problems. On the Yanmar 2GMF in his J/30, OTOH, removing the elbow and cleaning it out is part of annual maintenance. Rick Brass Washington, NC From: CnC-List [mailto:cnc-list-boun...@cnc-list.com] On Behalf Of Chuck S via CnC-List Sent: Sunday, August 09, 2015 9:35 AM To: CNC boat owners, cnc-list <cnc-list@cnc-list.com> Cc: Chuck S <cscheaf...@comcast.net> Subject: Re: Stus-List cleaning heat exchanger Hi Dwight, I do have the M4-30 and it when it ran hotter than normal, I clean the little tubes with 1/8" wooden rods I buy from an art supply or hardware store. I run my engine at 190 degrees. I thottle back if the temperature gets above that. To clean: With the engine off and the seacock shut, I remove both ends of the exchanger and simply push the wooden dowels through a few times. There are about 30 to 40 tubes, but it's pretty easy. A diesel mechanic recommended I remove the exchanger and have it acid cleaned to remove any scale from the fresh water side. I haven't done that. I heard of a product you use without disassembly, and then you flush it and replace your water and antifreeze mix. I'll try and find that. Chuck _____ From: "dwight veinot via CnC-List" <cnc-list@cnc-list.com <mailto:cnc-list@cnc-list.com> > To: cnc-list@cnc-list.com <mailto:cnc-list@cnc-list.com> Cc: "dwight" <dwight...@gmail.com <mailto:dwight...@gmail.com> > Sent: Sunday, August 9, 2015 8:20:01 AM Subject: Re: Stus-List Raymarine EV-100 and backbone wiring Hi Chuck I recall reading in one of your C&C posts that you have an M4-30 and that you dismantled and cleaned the heat exchanger. Is that correct and if so what did you find inside? I mean how it’s built and was anything clogging it? Also did you ever do any cleaning/maintenance where the salt water from the heat exchanger enters the exhuast gas line? My M4-30 runs great at 1600 rpm but when I run it at higher rpm’s it runs hotter than I think it should, like at 2500 rpm the temp gage climbs to boiling and sometimes 220 F but the engine is still smooth and strong, just hotter than I would like to see. I would like to see more water exiting the boat and I know my raw water pump is good since I have installed a new impeller with no noticeable change in performance and I know the raw water feed to that pump is not blocked, lots of flow into the bilge when I disconnect it from the pump. Can yo give me any advice from your experience. Thanks dwight Dwight Veinot C&C 35 MKII, Alianna Head of St. Margaret's Bay, NS d.ve...@bellaliant.net <mailto:d.ve...@bellaliant.net>
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