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Thread: muffler

  1. #21
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    HI Jackie, I recently suffered some similar symptoms. Mine were a minor change in the noise / rattle coming from the engine. This led me to run at lower RPM's. Coming back from Vallejo the noise got worse, a light popping sound. I shut down and sailed home. A week later out testing an AP the noise went up a notch, louder popping. I sailed home. It all turns out to be a build up of carbon and unburned diesel in the exhaust riser/mixer/exhanger. Just past the exhaust manifold. I have taken this heavy metal object off and have cleaned the passage with a chisel, wire brush, and a piece of standing rigging. Finally I have taken it to an auto shop for an overnight soak in there cleaning bath. THere was a lump in the path the size of a ping pong ball that 1/2 clogged the exhaust stream. A diesel mechanic told that for sure this would explain the symptoms.

    I wanted to offer an alternative means of getting information. On the day of the next Berkeley mid winters stand on the sea wall dressed in foulies with a cardboard sign, " Will crew for diesel advice".


    Brian
    Last edited by brianb; 12-02-2013 at 11:23 PM.

  2. #22
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    Quote Originally Posted by brianb View Post
    I wanted to offer an alternative means of getting information. On the day of the next Berkeley mid winters stand on the sea wall dressed in foulies with a cardboard sign, " Will crew for diesel advice".

    Brian
    Your solution sounds great. I assume the Olson 34 is fresh water cooled. I don't think I have that option on my Universal M15. I agree that there are different ways to get what one needs. Two years ago I approached Bob Grey @ Berkeley Yacht Club about hosting our first Round the Rocks race. The barter agreement was that in return I work race committee for a season of that club's midwinters. That was a very pleasant trade, especially since there is often little wind and I'd rather sit around and eat sandwiches on a beautiful boat than float around for hours on the Olympic Circle in Dura Mater.
    Last edited by Philpott; 12-03-2013 at 10:05 AM.

  3. #23
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    The fact your engine is raw water cooled makes no difference. You should still have a riser/anti-siphon/heat exchanger, or what ever they call it on Dura Mater. All boats will have a device to mix the raw water coolant with the exhaust stream and them pump it out the back. According to my local tractor mechanic this is the most common failure he sees in all diesel installations. The exhaust stream slowly closes down and the engine cylinders then don't empty fully after combustion, causing a noisy popping sound. A way to test this is to remove the this heat riser and run the engine for a minute with no exhaust (muffler). It will fill your cabin with exhaust, but only for a minute. If the engine runs well then that is the problem. When, and if, you do this the noise in the boat will be very loud. Kind of like the GTO all the hot guys in high school tooled around in.

    Of course you could have some other issue, but the fact your engine was making funny sounds and it ran sometimes, slowly getting worse, sounds like my symptoms and what the mechanic described to me.

  4. #24
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    When my Yanmar's exhaust system had arteriosclerosis, it got a Gucci new "chrome" exhaust elbow:

    Attachment 491
    Last edited by BobJ; 12-03-2013 at 04:39 PM.

  5. #25
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    Quote Originally Posted by brianb View Post
    All boats will have a device to mix the raw water coolant with the exhaust stream and them pump it out the back. According to my local tractor mechanic this is the most common failure he sees in all diesel installations. The exhaust stream slowly closes down and the engine cylinders then don't empty fully after combustion, causing a noisy popping sound. A way to test this is to remove the this heat riser and run the engine for a minute with no exhaust (muffler). It will fill your cabin with exhaust, but only for a minute. If the engine runs well then that is the problem. When, and if, you do this the noise in the boat will be very loud. Kind of like the GTO all the hot guys in high school tooled around in.
    This makes perfect sense to me. I just can't locate the heat exchanger on my own engine. I found this great article:

    http://www.pbase.com/mainecruising/heat_exchanger

    which describes the process you suggest. I'll go down and crawl around some more tomorrow.

  6. #26
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    Jackie, if I understand you and Brian correctly, you're focused on different ends of the cooling system.

    When the water pump draws water IN to cool the engine, it is raw (sea) water. Most diesels don't shoot this sea water into the engine directly, they pump it through a heat exchanger where the hot, fresh water that has gone through the engine can transfer its heat to the cold sea water. Apparently your engine is like mine - it DOES shoot the sea water into the engine directly. That's why you can't find a heat exchanger on it. But all this is happening on the water INTAKE side.

    What Brian is writing about is what happens after the hot water comes out of the engine, on the EXHAUST side. The elbow (shiny thing in my photo) sends the hot exhaust gasses to combine with the hot water exhaust in the lift can (the Vetus plastic part that melted) and then out the back of the boat.
    Last edited by BobJ; 12-03-2013 at 06:00 PM.

  7. #27
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    Default NEar your boat tomorrow

    Quote Originally Posted by Philpott View Post
    This makes perfect sense to me. I just can't locate the heat exchanger on my own engine. I found this great article:

    http://www.pbase.com/mainecruising/heat_exchanger

    which describes the process you suggest. I'll go down and crawl around some more tomorrow.
    Hi Jackie,

    I will be in Alameda tomorrow until 1 30 pm and could stop by Berkeley around 2 pm. If you want another set of eyes on the engine.

    Brian

  8. #28
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    Sep 2008
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    Saratoga
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    My little one lung Faryman diesel is raw water cooled, and the water jacket that was replaced a few years ago, (hot salt water on the alternator seemed bad), is already exhibiting small signs of corrosion.
    The previous owner, spliced in a Prestone flush kit tee just above the intake, and after every use, the engine is fresh water flushed with the flush kit hose in a 5 gallon bucket.
    I really think this continued practice has saved me some grief and expense.
    A little Mrs. Stewart's bluing in the bucket indicates the system is flushed through.

  9. #29
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    oops! Just got this email! I'll drive down to the boat right now (1:45pm) in case you stop by O Dock 212. That's the entrance nearest the Berkeley yacht club.

  10. #30
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    Aug 2013
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    LOL. (Laughing out LOUD!). Trust Ragtime! to want the Gucci treatment!

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