Why did my engine stop?

[skyflyer]

Happily motoring along in calm conditions with very little pitching or rolling and suddenly the engine starts to die, catches itself and then dies again.
Quick check that we aren't out of fuel (nowhere near) and I try to restart. It fires into life for ten seconds or so then dies. I repeat this two or three times then stop!
I go below and look at the bowl beneath the primary filter. This shows no sign of water nor of dirty fuel.
I then crack the bleed nut at the top of the engine fuel pump while the engine is turned over a couple of times, and fuel initially dribbles then spurts.
I do up the nut and try starting again. The engine starts, runs roughly for about a minute, gives a cough and a splutter and has run sweet as a nut ever since ( 5 hours at a stretch the very next day)
Any thoughts as to what happened? I am assuming that if we had dirty fuel or bio-sludge this would (a) show in the filter bowl and (b) would block one or other filter, necessitating a filter change to restart.
Could it have been water- but again this would show in the bowl would it not? An airlock - how did it get there?
Obviously without a known cause it's a bit of a worry as to when the engine might next suddenly decide to quit!
Grateful for any similar experiences and known causes you can offer

(28hp westerbeke Diesel engine in a sailing yacht)

 

[superheat6k]

My money would be something fuel related, perhaps a minor blockage which then cleared. Can you inspect the bottom of your tank somehow ?

Maplins sell cheap endoscopes that can be used underwater, and I would be happy to use mine immersed in diesel.

Otherwise perhaps the fuel has become aerated from the return, and the air has built up in the fuel line - did any air come out of the bleed point ?

 

[lpdsn]

Grateful for any similar experiences and known causes you can offer

I'd guess a fuel line blockage of some sort. Doesn't have to be completely blocked to cause problems. How easy is it to pump diesel through by hand using the lift pump? I certainly found it far easier after the problem was sorted. Does the engine run OK at tick over but play up when you try to give a burst of revs?

 

[pvb]

Had a similar experience with a VP sterndrive many years ago, eventually traced to a small piece of sponge which got sucked into the fuel pick-up pipe.

 

[rjp]

I had a similar problem last summer. Turned out to be a minute air leak through a joint in my fuel system. Eventually I assume a bubble formed large enough to stop the fuel flow. Once cleared the engine would run fine for many hours before the same thing happened again. Eventually found and tightened the offending joint, no problem since.

 

[michael_w]

Another vote for rubbish getting caught in the fuel pick up. I've had the same thing happen, on my boat. I suspect the plastic disk that was causing all the trouble came from the top of an additive bottle. I've also had the same thing with my old Land Rover. Didn't find the culprit, but a wire baloon on the pick up pipe solved the problem.

 

[Modulation]

And I had a similar problem 4 years ago.Turned out to be sludge in the bottom of the fuel tank getting through in choppy weather. I bit the bullet and drained the tank , cleaned it out, left it for weeks to dry out and sealed it up again. I also filtered all the fuel before refilling.
Mind you I was lucky in that I had a very large tank access panel.

My money would be something fuel related, perhaps a minor blockage which then cleared. Can you inspect the bottom of your tank somehow ?

Maplins sell cheap endoscopes that can be used underwater, and I would be happy to use mine immersed in diesel.

Otherwise perhaps the fuel has become aerated from the return, and the air has built up in the fuel line - did any air come out of the bleed point ?

 

[GrahamM376]

Had a similar problem last year, turned out to be a filter although it looked fine with no sign of sludge.

 

[viva]

Another vote for rubbish getting caught in the fuel pick up. I've had the same thing happen, on my boat. I suspect the plastic disk that was causing all the trouble came from the top of an additive bottle. I've also had the same thing with my old Land Rover. Didn't find the culprit, but a wire baloon on the pick up pipe solved the problem.

+1 when it happened to me it was diesel bug. Strands of gunk blocked fuel pick up in tank. Likewise there were no signs of contamination in filters

 

[BlueChip]

+1 when it happened to me it was diesel bug. Strands of gunk blocked fuel pick up in tank. Likewise there were no signs of contamination in filters

Had the same thing years ago, turned out to be flakes of rust from the steel fuel tank blocking the fuel delivery pipe

 

[Gordonmc]

Check the fuel tank vent isn't blocked somewhere.
If it is the air pressure in the tank won't equalise and there will be no sook in the feed pipe.

 

[Stu Jackson]

All good ideas. Happened to a skipper few weeks ago on our cruise. We aborted the cruise and sailed back home. Later that week his mechanic blew back through the fuel pickup hose from the filter that cleared whatever crud was in there. He's currently checking out his options, including pulling the fuel tank, which is a major undertaking. I designed a simple "blow back" hose for him with a T and two valves.