Preview: Marine Diesel Engines, Part 2 – Trouble-Shooting the Raw Water System

13 Responses So Far to “Marine Diesel Engines, Part 2 – Trouble-Shooting the Raw Water System”

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  Angela Humphries says:

  This short marine engine series is great for helping me become acquainted with my yanmar 3qm!

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  Graham Hart says:

  We have had a problem on our Yanmar 3YM30; with the cast iron? cooling water inlet fitting in to the exhaust elbow clogging up. This is another area worth checking, when trying to track down loss of water flow. Has cost us the seals on our fridge compressor twice now (in less than 250 hours total run time…..)

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  Wendy Friant says:

  I belong to the Royal Savage Yacht Club located on Lake Champlain, in Charlotte, VT. We plan a focus on boater education this coming year. Some of your videos would be excellent (I am currently working my way through marine diesel engines). I would love to show some of these videos to a group. I don’t know if that is “allowed”. We are a small club… and membership is only $60/year, even if you join as a family, so our coffers are not exactly overflowing. Would you be ok with me showing these videos to members (and promoting your service in the process). If not, is there some sort of a group membership we could discuss that would allow this?
  Many thanks, Wendy Friant, Past Commodore, RSYC. You can learn more about us at rsyc.org.

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  Wendy Friant says:

  I belong to the Royal Savage Yacht Club in Lake Champlain, in Charlotte, VT. We plan to focusing boater education this coming year. Some of your videos would be excellent (I am currently working my way through marine Diesel engines). I would love to show some of these video to a gro. I don’t know if that is “allowed”. We are a small club… and membership is only $60/year, even if you join as a family, so our coffers are not exactly overflowing. Would you be ok with me showing these videos to members (and promoting your service in the process). If it, is there some sort of a group membership we could discuss that would allow this?
  Many thanks, Wendy Friant, Past Commodore, RSYC. You can learn more about us at rsyc.org.

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  Kenelm Russell says:

  Here is a good trick to use if your engine seacock or intake hose is plugged before the water gets to the strainer. Disconnect the intake hose at the strainer. Grab your pressure can boat horn and insert the hose end into the horn and hold tight to seal it. Blow the horn. You will hear a giant sized bubble exit the boat. Quite often this is all it takes to dislodge the blockage. Saves a lot of work taking things apart!

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  Paul Forman says:

  Newbie here! When you replace an impeller, do you need to grease it as well?

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    Michael Costello says:

    Suggest you try using dialectric grease. It’s used to protect electrical connections but it really helps when installing your impeller.

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  Linda Austin-Morin says:

  If the impeller fails, would it/should it be replaced prior to getting back underway?

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  Gary Bain says:

  In watching the video I see that you have a strainer on the outside of the hull. Many boats do not. I think it would be a good idea to suggest for those that do not have the strainer, and they determine the blockage is between the thru hull valve and the outside of the boat, be it a piece of kelp or plastic bag, to carry a wooden dowel that would pass through the valve to clear the passage.

  Another note would be if it is a plastic bag sometimes the bag will drop off when you do shut the engine off.

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  Jon Bardo says:

  Serious wet exhaust problem on a work boat. The boat was overloaded with traps that put the wet exhaust pipe under water. The boat lay at the dock awaiting the tide with the engine off. The exhaust hose was 6″ in diam. and was full of sea water( a lot of weight). When the engine was started the weight and added pressure of the exhaust gasses pulled the exhaust hose off of the elbow. Both bilge pumps came on( but 6″ of water is a formadable problem at best), the boat took a port list, putting the stern under at about the same time that the boat was run aground. The reverse gear and the engine took on water and are being repaired. Always check your boats exhaust hose and clamps(2 at each connection ) on a regular maintenance schedule!! Might be a good reason to have dry exhaust on work boats that may take on weight(cargo) that would put the exhaust under water. Just saying! JCB

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  Jon Bardo says:

  Yes the broken impeller pieces can clog the heat exchanger and should be removed.

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  David Tew says:

  If impeller vanes have broken into small pieces is there a chance they may pass into the inside the heat exchanger and block cooling tubes?

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    Captain Nemo says:

    Great question David. I had the same idea.