[C38] carbon build up in exhaust elbow

D. R. Strong drstrong at ucdavis.edu
Fri Feb 26 14:32:07 EST 2010


Wow, I now have a "plus" side story to tell to my pals who have moorings 
closer to the sailing grounds. We have to motor for about 20 minutes 
(2,800 rpm on the Yanmar 3GM), 2+ nm from Emery Cove to the end of the 
dilapidated, severe navigational hazard of the abandoned Berkeley Pier 
to catch anything but a dead on head wind.  Benefits sometimes come in 
strange packages.
    Tom. I have never failed to learn something from your posts. I 
assume that your boats are on Lake Lanier in Atlanta, no?
Regards, Don
   

Tom T. wrote:
> I have to agree with Dave McCarthy about the carbon buildup on diesel
> exhaust systems.  All engines hate to run cold but diesels particularly.
>
> When we were close to our final destination we would make it a point to
> crank up and motor sail or drop sails and motor the last couple of miles
> with at least 1500 rpms to completely warm our engine to remove
> condensation in the engine oil and clean out the exhaust carbon while at
> the same time heating our hot water tank for our hot showers at the end of
> the day.  The cleansing benefits of a hot engine don't really start to work
> until after reaching full temperature under a load.
>
> After many years, our exhaust was still clean and our engine oil never
> showed any signs of moisture.  
>
> Tom Troncalli
>
>
>
>
>   
>> [Original Message]
>> From: D McC <cat38skip at yahoo.com>
>> To: Catalina 38 Listserve <listserve at catalina38.org>
>> Date: 2/26/2010 9:21:24 AM
>> Subject: Re: [C38] C38s with Yanmar exhaust elbows
>>
>> We had a similar loss-of-power problem on our previous boat with a single
>>     
> cyl Yanmar. The exhaust was reduced to less than 1/8" due to carbon
> buildup. This was a common problem for a number of boats in our marina. The
> run from the slip to sails up was less than 10 minutes. The mechanic said
> that if we did not run the engine at temperature for at least as long as it
> takes to warm it up, we would continue to have carbon build up problems. I
> don't know if this is the issue with your engine, but longer run times
> seemed to solve our problem. 
>   
>> Dave McCarthy
>> C38 #148 - Pretty Lady
>> San Francisco, CA 
>>
>>  <><><><><><><><><><><><><><><><><><><><><><><><><><><>
>>
>>
>> Common Sense is a rare gift from the Gods.
>> Most people have only technical training! 
>>
>>
>> <><><><><><><><><><><><><><><><><><><><><><><><><><><>
>>
>>
>> The gods do not deduct from man's allotted span those hours spent in
>>     
> sailing.
>   
>>
>> ----- Original Message ----
>> From: Phil Gay <eyriepg at comcast.net>
>> To: Catalina 38 Listserve <listserve at catalina38.org>
>> Sent: Thu, February 25, 2010 8:43:25 PM
>> Subject: Re: [C38] C38s with Yanmar exhaust elbows
>>
>> I just replaced the exhaust elbow where the water is injected to the
>>     
> exhaust
>   
>> on my 1996 Yanmar 3GM30.  The engine ran well before but I did it as
>> preventative maintenance after 14 years of service.  I expected to see a
>> plugged casting but it was really clean.  I plan to keep it for a spare. 
>>     
> I
>   
>> don't understand why some clog and others don't.
>>
>> Phil Gay
>> C38 049 Que Linda
>> Everett, WA
>>
>> -----Original Message-----
>> From: listserve-bounces at catalina38.org
>> [mailto:listserve-bounces at catalina38.org] On Behalf Of Robert Miller
>> Sent: Thursday, February 25, 2010 3:18 PM
>> To: larrypi at linkline.com; 'Catalina 38 Listserve'
>> Subject: [C38] C38s with Yanmar exhaust elbows
>>
>>
>> I was gradually losing power from my Universal 5424 diesel.  Last week I
>> took her out and was only able to maintain 1700 rpm at full throttle. 
>>     
> With
>   
>> visions of a new engine haunting me I called the legendary Alfredo who is
>> one of the best known diesel mechanics in San Diego.  He ran the engine,
>> checked out the injectors and said "your engine is fine."  "It's probably
>>     
> an
>   
>> exhaust restriction."  He pointed to the Yanmar elbow and said that they
>>     
> are
>   
>> prone to clogging.  20 minutes later he had the exhaust system removed and
>> broke the elbow with a hammer.  What had previously been a 1 3/4" passage
>> was now completely clogged with carbon with two passages less than 1/8" in
>> diameter.  He is fashioning a new pipe system minus the elbow and will
>> install a new exhaust flange.  He will be back next week to install it.  I
>> will let you know how it works out.  If anyone has one of those elbows and
>> is losing power, check it out.
>>
>> Bob Miller
>> "Bolero" #113
>> Southwestern YC, San Diego
>>
>>
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>>     
>
>
>
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>   

-- 
Donald R. Strong
Professor
Section of Evolution and Ecology
University of California Davis
95616
530 752 7886

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