[C38] C38s with Yanmar exhaust elbows

[D McC]

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! 


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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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