{Stus-List} Engine trouble

David Knecht-charter david.knecht at uconn.edu
Sun Oct 28 18:17:12 EDT 2007

I need some engine (Yanmar 3GM) help from the experts.  I went to  
take the boat over for winter haul out today.  It was blowing 25-30  
and I was a bit hesitant, but it was offshore wind so waves should  
not be too bad.  I was motoring halfway out of the harbor and things  
went bad.  I went over a fairly large motorboat wake and a bit later,  
the engine began to slow.  I turned around and headed back and the  
engine oontinued to slow for about another minute and then quit  
completely. We got a partial genoa unfurled and proceeded to work our  
way back up to weather to the mooring and got the mooring line  
secured on the second try.  It was a bit hairy, tacking through the  
mooring field in those conditions, but thank goodness I didn't have  
to try and land at a slip.

Anyway, suggestions on where to start when I go down to try to fix  
this would help.  From other stories I have read, a clogged fuel  
filter from stirred fuel seems like a possibility.  However, we were  
not in heavy seas, and the one wake we went over was no worse than  
many we have gone over all summer and it was just one wake.  I looked  
at the filter when we got back, and the fuel in the primary bowl and  
the filter looked fine to me.  However, I have never had a clogged  
filter.  Should it be obvious?  I have antimicrobials and every other  
additive you can mention in my diesel fuel, and I drained the tank  
this spring and could find no evidence of crud on the bottom.  I did  
not pull the tank, so am not positive, but I stirred and scraped and  
pumped from the bottom, and it came out clean looking.  I filled the  
tank in May, and I have used the engine so little that it is still  
the same fuel in there.  When I tried to start it at the mooring, the  
engine would turn over very roughly and then die as if not hitting on  
all cylinders.  I am hoping that the gradual slowing of rpm initially  
and the rough starting will mean something to someone.  Thanks- Dave

Masquerade- 1982 C&C 34
New London, CT

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