[C320-list] exhaust elbow question

[Robert Seastream]

I start my 2002 Yanmar 3GM30F up and idle around 1500 or so for a few 
minutes, which is all it takes to reach operating temp of about 160.  
Then I drop it to dead idle (~900), engage gear and go.  I usually run 
about 3000 when under way.  As to deliberately cranking the engine 
while preventing starting, I suppose that may make some people feel 
more comfortable.  Don't do it for long lest you flood the 
'aquamuffler'; such flooding might back up into your exhaust manifold, 
thence on into the engine-not good.

Bob


On Oct 4, 2006, at 11:23 AM, Jeffrey Hare wrote:

> Hi Guys,
>
> Don't sweat the warmup/revving thing.  Most agree you shouldn't load it
> until it's warmed up, but reving a diesel after starting it in the 
> summer is
> simply a non-issue.  In the middle of winter is a different story 
> because
> the oil doesn't flow well.
>
> Revving a *Gas* engine that hasn't warmed up for a couple minutes in 
> cool or
> cold weather is a different story.  Gasoline washes the oil off the 
> cylinder
> walls, while diesel doesn't really suffer from that phenomenon given 
> that
> Diesel fuel *is* oil.
>
> Clean oil, clean air, and clean fuel, running it hard/fast it'll 
> outlive
> many of us.
>
> -JeffH
>
>
>
> -----Original Message-----
> From: jonvez at comcast.net [mailto:jonvez at comcast.net]
> Sent: Wednesday, October 04, 2006 10:52 AM
> To: John Van Vessem; C320-List
> Subject: Re: [C320-list] exhaust elbow question
>
> John,
>
> I am certainly not an expert on this, but the info. I received was 
> from a
> two day diesel class I took that was put on by Mack Boring....I guess 
> I'm
> back to being confused??
>
> Regards,
>
> Jon Vez
>
> -------------- Original message --------------
> From: John Van Vessem <jvanvessem at sbcglobal.net>
>
>> Running a cold engine up to full RPM is probably the worse thing you 
>> can
> do to
>> any engine. The Yanmar manual says that you should run the engine up 
>> to
> full
>> throtle prior to shutting down, when the exhaust is hot and all 
>> bearings
> are at
>> their disign tolerance.
>>
>> John Van Vessem
>> Sojourn 645
>> Vallejo Yacht Club
>>
>>
>>
>> ----- Original Message ----
>> From: jonvez at comcast.net
>> To: Allan.Field at comcast.net; C320-List
>> Sent: Wednesday, October 4, 2006 5:02:18 AM
>> Subject: Re: [C320-list] exhaust elbow question
>>
>>
>> Koen,
>>
>> I posted several questions related to the exhaust elbow as I was
> interested in
>> proactively replacing mine (my boat is in it's 8th season in salt 
>> water).
>>
>> My confusion was whether the elbow was custom made by Catalina like 
>> the
> muffler,
>> or whether I could get it from a Yanmar dealer--than answer is BOTH. 
>> Some
> hulls
>> (with the Yanmar) had a custom elbow made by Catalina...even though I
> suspected
>> this was the case on mine, I couldn't confirm until I went to a local
> Yanmar
>> distributor myself. Even Catalina couldn't answer this question....The
> good news
>> is that if you do have a custom elbow from Catalina, you can indeed
> replace with
>> a stock Yanmar elbow...The bad news is, you need to buy 3 pieces (for
> about $360
>> vs about $160 for just the elbow). The Catalina elbow is a one piece
> elbow,
>> whereas the stock parts have a manifold, an adjusting screw connector 
>> and
> the
>> elbow. Once you have replaced with the stock parts, you will only 
>> have to
>> replace the elbow (top part) going forward....
>>
>> As for time, Mr. Douglas had suggested 5-8 seasons is a good time to
> replace.
>> One suggestion on keeping the buildup under control from Mack Boring 
>> is to
> start
>> the engine at full throttle and bring it back to idle as soon as the
> engine
>> starts...This will blow a lot of the build up out and presumably 
>> delay the
>
>> inevitable...
>>
>> Regards,
>>
>> Jon Vez
>>
>> -------------- Original message --------------
>> From: "Allan Field"
>>
>>> Koen - There are 2 concerns with the exhaust elbow. The first is 
>>> that it
>
>>> clogs over time and will impact engine performance. The second is 
>>> that
> it
>>> eventually gets pinhole leaks. Both happened on my previous boat. 
>>> Trust
> me
>>> when I say that you don't even want to think about the mess you will
> have if
>>> the elbow gets a pinhole leak. The engine compartment fills with 
>>> black
> soot
>>> that never completely goes away no matter how much you clean, clean,
> clean,
>>> and clean some more.
>>>
>>> I intend to replace my elbow prophylactically over the winter at 
>>> about
> 500
>>> hours, change the hose to the aqua lift muffler, add a hump hose at 
>>> the
>>> muffler, and pull the muffler, send it back to Catalina, and have a
>>> duplicate muffler made to sit on a shelf until when I need it. Again,
> you
>>> don't even want to think about the mess if these parts fail.
>>>
>>> Allan S. Field
>>> Sea Shadow - #808
>>> Columbia, MD
>>>
>>> -----Original Message-----
>>> From: c320-list-bounces at catalina320.com
>>> [mailto:c320-list-bounces at catalina320.com] On Behalf Of Koen 
>>> Bennebroek
>>> Sent: Tuesday, October 03, 2006 9:05 PM
>>> To: c320-list at catalina320.com
>>> Subject: [C320-list] exhaust elbow question
>>>
>>> I seem to remember someone mentioning that the exhaust elbows on 
>>> C320's
> get
>>> clogged and are recommended to be replaced every so often..
>>> My local mechanic, who will do the very first service on our boat 
>>> soon
> (so
>>> we do not have experience either with him or with the engine
>>> service in general), recommends we order the elbow and gasket from
> Perkins
>>> (I believe tadiesel sells them?) in advance to save time.
>>>
>>> Is this a good suggestion? We have purchased the boat used 2 seasons
> ago, so
>>> I have no idea what the history of this part is.
>>>
>>> Thanks for any suggestions,
>>>
>>> -Koen
>>>
>>>
>>>
>>>
>
>