[C320-list] exhaust elbow question

[John Van Vessem]

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 <c320-list at catalina320.com>
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" <Allan.Field at comcast.net> 

> 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 
> 
> 
> 
>