[C320-list] exhaust mixing elbow

[Jack McDonough]

If you come down through Portsmouth Harbor, you must start in Great Bay at 
Dover Point. (I grew up in Dover.) That's a long way in and out, isn't it? 
And Great Bay looks to have some swirly currents. And the current under 
those bridges in Portsmouth are swift, with a capital S.




----- Original Message ----- 
From: "Robert Seastream" <robert.seastream at comcast.net>
To: <C320-List at Catalina320.com>
Sent: Friday, September 19, 2008 5:12 PM
Subject: Re: [C320-list] exhaust mixing elbow


> We have about an hour run to get downriver and out of Portsmouth  harbor 
> to offshore.  We run at 2400 for fuel economy, 3000 if we have  to hustle 
> to make the bridge openings.  3200 is the continuous max  rating for our 
> Yanmar 3GM30F.  Once or twice a year, I run WOT (3600  rpm; coincides with 
> the one hour engine rating) for about 15 minutes.   Never had 'smoke' 
> issues, however our engine only has about 300 hours  on it.  Engine temps 
> range from 160 to 180 degrees farenheit under  those respective 
> conditions.
>
> Bob Seastream
> Intuition # 906
>
> On Sep 19, 2008, at 6:04 PM, Allan S. Field wrote:
>
>> We make sure that every time we run the engine, we run at 3,000 rpm  for 
>> at
>> least 5 minutes.  600 hours and no smoke although we intend to pull  and
>> clean the elbow prophylactically this winter regardless.
>>
>> Allan S. Field
>> Sea Shadow - #808
>> Columbia, MD
>>
>> -----Original Message-----
>> From: c320-list-bounces at lists.catalina320.com
>> [mailto:c320-list-bounces at lists.catalina320.com] On Behalf Of Crosby 
>> Roper
>> Sent: Friday, September 19, 2008 5:42 PM
>> To: c320-list at catalina320.org
>> Subject: [C320-list] exhaust mixing elbow
>>
>> Thought I'd pass this along for general lesson learned file. In july  on 
>> my
>> way back from Catalina island to San Diego, I noticed that when I  ran 
>> the
>> RPM's up to 3200, I got a bit of black/brown smoke from exhaust.  Since 
>> water
>> tanks were full and there was a bunch of stuff on board, I figured 
>> probably
>> just overloading the engine was the problem. On my next trip to  catalina 
>> on
>> Labor day, I noted smoke at 3000 RPM. To make a long story short, the
>> problem progressed rap[idly over the next 30 hrs of engine use to  the 
>> point
>> where even at 2000 RPM i was seeing smoke. We limped back to the  slip 
>> and
>> called mechanic ( to whom I had spoken while in Catalina and who had 
>> advised
>> me that problem was likely a clogged exhaust mixing elbow and OK to  run
>> engine at low RPM as long as it was not producing smoke.) He came  out on
>> Monday and problem was indeed exhaust mixing elbow. The engine is 3 
>> years
>> old and has about 220 hrs on it. He admonished me for not using the  boat
>> enough (in front of my wife, which should work out well for future 
>> sailing
>> schedule) and for babying the engine. So, for anyone else who tends  to 
>> baby
>> their diesel, run it frequently and run it hard. But we already know
>> that!Crosby Roper, VMD
>> Tethys # 1054
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>