Rob; Carbon buildup in the exhaust mixing elbow can be a problem on the 2 cylinder Yanmar.. Causes back pressure that hurts performance, and eventually caused the the engine to not start on a friend's C&C 29. My friend Bob, who makes his living as an engine mechanic, cleans out the elbow on the 2 cyl Yanmar in the J30 he races every 200 engine hours as part of periodic maintenance. If you've not had something like that done in 16 years, it might be something else for your mechanic to look into. Rick Brass Happy owner of a Kubota based Universal diesel Washington, NC -----Original Message----- From: Stus-List Sent: Jun 26, 2022 11:58 AM To: Stus-List Cc: Robert Abbott Subject: Stus-List Yanmar 2 GMF The mechanic took a quick look on Friday and felt it was a fuel issue....maybe dirty filters (although the tank was out of the boat 2 years ago and pressure cleaned, both primary and secondary fuel filters changed at the same time).
Chuck, I did that myself (didn't repair the bottom of the tank) but everything else....emptied the fuel tank of 15 gallons of diesel (donated it to the club's tractor), took the tank to a machine shop where they repaired the two pin holes, put it back in, new fuel and new fuel filters. The mechanic did notice some diesel leaking from a line fitting going into the small Yanmar fuel filter.... said a quarter inch tightening might solve the problem as this might be an air leak. When I said earlier the engine has not been serviced in 16 years, I meant it had not had a diesel mechanic service it.....I do an oil change every Fall, fuel filters changed regularly, have replaced all the engine hoses, air filter, water and alternator belts, water pump impellers, etc. This work i do myself but when it comes to more complicated things, \i will leave that to the mechanics who know what they are doing (or should) If it something like dirty or failed fuel injectors, a failed fuel pump, etc, etc, best the mechanic diagnose the problem and fix it. Rob Abbott AZURA C&C 32- #277 Halifax, N.S. On Sun, Jun 26, 2022 at 10:03 AM Novabraid via CnC-List wrote: Rob, Recommending two things: 1. Change both filters and perform this task annually (or more often if your source of diesel is questionable.) 2. Find out if your mechanic is willing to have you “help” perform the filter change as it will likely be the first thing he’ll want to do. You really need to learn how to make filter changes and to learn how to bleed the fuel system once a filter has been changed. Changing the fuel filters will reveal a lot since you’ll be able to see what’s contaminating the fuel system or causing a blockage. Its conceivable that your primary (or lift) fuel pump that brings fuel to the engine from the fuel tank may have a worn or leaky diaphragm. Look for traces of diesel around the edges of the pump housing. An easy fix but harder to diagnose if you can get the engine to run a full speed after you change the filters. Not sure what marine education options are available in Halifax but its always good to think about taking a marine diesel course for peace of mind. I did it about 5 years ago at Annapolis School of Seamanship and it’s given me confidence to do some basic problem solving and service myself. Chuck Gilchrest S/V Half Magic 1983 Landfall 35 Padanaram, MA From: Robert Abbott via CnC-List Sent: Sunday, June 26, 2022 9:38 AM To: cnc-list@cnc-list.com (mailto:cnc-list@cnc-list.com) Cc: Robert Abbott Subject: Stus-List Yanmar 2 GMF Went to take the boat out Friday for a short sail .....motoring out heading into a12 knt breeze....started to increase the RPM's and found the engine wouldn't rev about 2,100 RPM's ....marine diesel's are not supposed to be that complicated but they are to me. I wouldn't know where to start to trouble shoot....getting a mechanic to deal with it this week. I spoke to him and told him the situation and he thinks it is a fuel problem....engine not getting enough fuel....my fuel tank and fuel should be clean as I had the bottom of it replaced 2 years ago and the 2 fuel filters replaced. He thinks one or both of the filters are restricting the fuel flow.....I hope he is right but I don't think so. Possibly many are causes....restricted fuel injectors, fuel pump, etc. ....the engine has never been serviced in the 16 years I have had the boat Any insight or guidance to help greatly appreciated. Rob Abbott AZURA C&C 32 - #277 Halifax, N.S. -- Joel Delamirande www.jdroofing.ca (http://www.jdroofing.ca)
