David,
Westerbeke/Universal calls it an exhaust riser or exhaust elbow. At the end of the exhaust manifold, you will find a connection to an elbow made of cast aluminum (at least that is what the elbow in my M35B is made of). The side of the riser/elbow has a tapped hole with a plug very close to the highest point, and into this you put a fitting for the hose carrying raw water from the heat exchanger. If I recall correctly, the hose is ¾ ID on my engine. Inside the elbow/riser is a sort of shelf or baffle that causes the hot water to fan out and cool the hot exhaust as it goes out of the elbow and into the exhaust hose. The PO had used a 45 degree elbow on the exhaust of the engine he installed in 2000. The 45 degree elbow, BTW, turns out to be a very bad idea on an engine that is mostly below the waterline. When I replaced the original M35 in 2010, I switched to a riser that routes the exhaust up for 6-8, and then straight down to the muffler. I looked at the old 45 degree elbow and found no carbon deposits or significant corrosion after 10 years of service. Made me wonder what the difference was that caused Yanmar engines to have so many problems. Rick Brass Washington, NC From: CnC-List [mailto:cnc-list-boun...@cnc-list.com] On Behalf Of David Knecht via CnC-List Sent: Saturday, November 15, 2014 9:27 AM To: Robert Abbott; CnC CnC discussion list Subject: Re: Stus-List Exhaust mixing elbow This discussion made me think about the situation on my boat with a Universal M4-30. I looked at the engine diagram and parts list online and found no mention of a mixing elbow. Is this a Yanmar specific issue? If so, how does the Universal handle exhaust? Dave On Nov 15, 2014, at 9:11 AM, Robert Abbott via CnC-List <cnc-list@cnc-list.com <mailto:cnc-list@cnc-list.com> > wrote: On 2014/11/13 8:23 AM, John and Maryann Read via CnC-List wrote: John Your mixing elbow is original ie 32 years old......I am assuming it has spent its life in a 'salt water environment'. If so, there has to be some corrosion taking place on the inside. A mixing elbow is not an expensive item and if you have taken yours off and put it back on, then do yourself a favor and replace it before it fails at the most inopportune time. In 2012, a fellow club member with a 1984 C&C 32 had his mixing elbow 'split' at the top of elbow spewing salt water and gases into his engine compartment while motoring up the coast. He made it back to the club O.K. but he then lost several weeks in the sailing season getting someone to replace it for him. I took his old mixing elbow and cut it open to examine it......while the outside wall looked fine, the inside was in pretty rough shape. And the problem wasn't carbon buildup but salt water corrosion. The following season, I replaced mine......I deem it preventable maintenance and what will eventually fail. Rob Abbott AZURA C&C 32 - 84 Halifax, N.S. Our 34 has the original Yanmar 3GM which is working like a charm. How does one tell if the mixing elbow is due for replacement??. Ours still has the original mixing elbow which we removed and inspected about 12 years ago. It was fine. Lots of water comes out the exhaust and engine performance is fine. Engine is used mostly for motoring in and out of the mooring field with periodic runs of an hour or so to get to the starting line. I was thinking of removing the hose and use a mirror and spot light to look inside?? John and Maryann Legacy III 1982 C&C 34 Noank, CT --- This email is free from viruses and malware because avast! Antivirus protection is active. http://www.avast.com _______________________________________________ This List is provided by the C&C Photo Album Email address: CnC-List@cnc-list.com <mailto:CnC-List@cnc-list.com> To change your list preferences, including unsubscribing -- go bottom of page at: http://cnc-list.com/mailman/listinfo/cnc-list_cnc-list.com _______________________________________________ This List is provided by the C&C Photo Album Email address: CnC-List@cnc-list.com <mailto:CnC-List@cnc-list.com> To change your list preferences, including unsubscribing -- go bottom of page at: http://cnc-list.com/mailman/listinfo/cnc-list_cnc-list.com Aries 1990 C&C 34+ New London, CT
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