Hi Kim Thanks for this. It is what I'm worried about. The boat has started to blow extra smoke on start and I'm thinking unburned diesel. It also blows smoke when you idle down for a bit and then rev up again. Once warmed up it seems fine. I've got a mechanic coming in a couple of weeks (they are backed up here in Victoria).
What I worry about is the slippery slope on an old engine. It is 1981 with around 1800 hours and raw water cooled. It runs fairly nicely but..... I also worry about the cost of a new engine which would not materially change the value of the boat - as people were saying earlier - boats cheap, parts expensive. How many boat units did getting the injectors cost if you don't mind sharing. Don -----Original Message----- From: Kim Brown [mailto:kimcbr...@comcast.net] Sent: May-13-13 2:50 PM To: cnc-list@cnc-list.com Subject: Stus-List Overheating due to plugged knuckle Don Just went through this with my 3GMF30. Had Diesel Dan (really) out because we are headed to the Abacos next month. (anyone going to be there for Regatta Time?) I was suspicious of injectors- boat was running but xtra smoke on start, oily exhaust water. So better here than there. Had the injectors rebuilt and as part of the looksie he checked elbow and assorted other potential trouble spots. The knuckle was almost closed with gunk and was replaced. Never did overheat but that may be more because there is flow tapped off for my dripless allowing some flow to continue besides the meager amount still passing through the knuckle. The injector rebuild really worked wonders- thought it was running ok before but now smoke is minimal, pops right off, runs cooler and smoother. My guess is the gunk was unburnt fuel building up. Your mileage may vary but that is another path to explore..... I had replaced the elbow about a year ago and the knuckle was fine then so it built up relatively quickly. And I haven't sucked an impeller lately (on my FWC the vanes hang up at the front end of the heat exchanger and are a PITA to extract). Kim Brown Trust Me 35-3 ____________________________________________________________________________ Message: 3 Date: Mon, 13 May 2013 10:44:51 -0700 From: "Don Jonsson" <dbjons...@shaw.ca> To: <cnc-list@cnc-list.com> Subject: Stus-List Overheating due to plugged knuckle Message-ID: <003f01ce5001$9250c7c0$b6f25740$@ca> Content-Type: text/plain; charset="us-ascii" Hello all I have an elderly Yanmar 3GMD engine that is raw water cooled. It has plugged twice in the last two years where the water goes through a knuckle into the mixing elbow. The first time (summer before last) was some solid bit that had gotten stuck - how it got there I don't know. The last time (last week) was due to a tar like substance gumming up the knuckle. Easy to clear and I was on my way, but is this a harbinger of something more serious. I took the mixing elbow off a few years back and cleaned it, guess it is time to do that again. Is the plugging coming from the exhaust and working its way into the knuckle - for example unburned diesel? Thanks for any insight. Don _______________________________________________ This List is provided by the C&C Photo Album http://www.cncphotoalbum.com CnC-List@cnc-list.com
