I wouldn't say it is that rare with small engine. Yanmar engines have a weakness to this regard. The fuel pump is a rubber diaphragm activated by one of the engine cam. Over the year, the rubber membrane can start leaking through a crack in the rubber. When it starts leaking, the diesel goes in the pan, where it start mixing with the engine oil (not a good thing). A small leak will go unnoticed until it develop to a substantial leak. The leak start filling up the pan until such a point when the pressure coming from the piston initiate self burning in the pan. The engine then goes wild and pulling down the throttle does not do much. I happened to me once and this when I discovered this weakness. When checking the engine oil, beware if the level seems to increase or remain stable where there should be a slight decrease. Look also if oil gets darker with lower viscosity. If the engine is getting old, I suggest preventive replacement of the pump membrane. Not a big deal to replace.
Antoine (C&C 30 Cousin) Le 2013-05-26 à 00:03, Martin DeYoung a écrit : > Back in my Merchant Marine school days, during a diesel engine maintenance > class a video was shown detailing what happens when a large displacement > diesel engine runs away, uncontrolled by the governor as it fed on lube oil > through the supercharger seals. Just before it failed (exploded) you could > see fire shooting out between the block and head. > > When attempting to stop a runaway diesel do not place your hand over the air > intake. Use foulweather gear or similar sacrificial air blocking material > that will conform around the air intake. If you have a Halon (Calypso’s > engine space has a 7.5lb auto-deploy Halon system in place) or a larger CO2 > extinguisher on board they may be used to slow the engine slightly to make > the stopping easier. > > This sort of failure is rare in small auxillary diesel engines, but more > likely with turbocharged engines. If a pleasure boater (power and sail) does > basic maintenance (do not over fill the lube oil) and every few years calls > in an expert to check the more complicated systems (especially the injection > pump, head bolt torque, and turbo seals) the risk of runaway should continue > to be small. > > Martin > Calypso > 1970 C&C 43 > Seattle > From: CnC-List [cnc-list-boun...@cnc-list.com] on behalf of Josh Muckley > [muckl...@gmail.com] > Sent: Saturday, May 25, 2013 7:16 PM > To: cnc-list@cnc-list.com > Subject: Re: Stus-List Fwd: Stopping a diesel > > So let me get this straight: > Run away engine - gonna blow. Decompress - gonna blow > Sounds like a dammed if you do dammed if you don't. > So don't decompress. Good to know for the normal "non-emergency" shutdowns. > I'm still gonna do it when shutting of the fuel and air don't kill the engine. > Thanks for checking me and the books, > Josh > -- > _______________________________________________ > This List is provided by the C&C Photo Album > http://www.cncphotoalbum.com > CnC-List@cnc-list.com
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