Astute observation, Francois. The 1,2, and 3 cylinder Yanmars seem to have consistent problems with the exhaust mixing elbow getting clogged by carbon deposits where the cooling water is injected into the elbow. And it is not a salt water problem.
A friend's 29-2 with a 2GMF15 was completely blocked and pumping no water at all when we went to start the boat just 2 weeks after an oil change this spring. We started diagnosing the problem at the raw water strainer and worked through the cooling system from front to back. Should have started with the exhaust elbow. Who would think it would clog up in the first place? A friend who is a diesel mechanic with a Yanmar engine in his J Boat says that you should remove and clean the elbow once a year or with every oil change. It's one of the reasons he keeps talking about replacing his Yanmar with a low hour Beta he happens to have in his shop. Rick Brass Washington, NC From: CnC-List [mailto:cnc-list-boun...@cnc-list.com] On Behalf Of Jean-Francois J Rivard via CnC-List Sent: Wednesday, August 10, 2016 11:26 PM To: cnc-list@cnc-list.com Cc: Jean-Francois J Rivard <jfriv...@us.ibm.com> Subject: Stus-List Stu-list How long before the raw water pump fuse water out the tailpipe? Hi Lorne, How long has it been since you took the exhaust mixing elbow off and took a look at it? The local 'Experts' were telling me that clogged elbows were a salt water boat problem.. Not so. -Francois Rivard 1990 34+ "Take Five" Cumming, GA
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