Diesel cutting out - why?

alisdair4

alisdair4

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Two days ago we were motoring in Loch Fyne when our engine (Volvo Penta MD11c) cut out for no apparent reason. The engine had been running at about 1500 RPM for about 4 hours at that point. Fearing the worst, I hoisted sail and we made port in a professionally satisfying fashion (sailing alongside). Anyway, the engine re-started and ran satisfactorily for another 6 hours yesterday, and 4 hours today. The oil is clean; the exhaust discharges water, and so I am at a loss to know why this happened and, more importantly, if it will recur. My immediate thought was a fuel blockage, but the fuel filter seems OK.
 
cutting out

Need a little more info, did it die instantly of did it splutter. have you checked the water seperator. When it restated did it start straight away or did you have to crank for a while.
Sorry but without a little more info its hard to narrow down possable causes.
 
MORE INFO

Sorry, that was a little thin! When it died, it cut out almost straight away. It restarted after a couple of turns, and then cut again out as soon as it was put into gear. The following day, it ran quite happily for 6 hours. Today, when I finally checked the separator, there was about 4mm of water in it. I drained this, and she ran for 4 plus hours today without a problem. I hope this helps?
 
cutting out

OK, so because it died straight away that narrrows things down a little, I take it there is an electric stop/start solenoid, or is it a pull cable? If electric you need to check that the solenoid is fully engaged (or disengaged depending on the type) when the engine is running, if its a pull cable just check the cable ends where it attaches to the engine to make sure it is operating the linkage fully in both directions, it may be that the lever on the fuel shut off is partially closed when running.......or the return spring may be broken.
Water in the fuel would give smoke and rough running but from your descrption it sounds unlikley.
Let me know what the outcome was with the investigation
 
Only a couple of things will stop a diesel so nothing to do with clean oil or water from the exhaust.
lack of fuel (blockage or air lock)or lack of air being most common .Almost certainly not air in the system as it wouldn't go again without bleeding.
Could have been a fuel blockage possible dirt in fuel line.
The fact it died when you put it in gear would have made me think you had something round the prop. Could you have caught anything round the prop and in effect stalled the engine? I would have checked I could rotate the shaft by hand if this had happened. Unlikely this would clear itself though.
 
I have sailed with an MD11 C quite a bit.

I have only known it stop once and that was in roughish conditions. It restarted straight away. We replaced the fuel filters as a precaution.

It even kept going when a valve dropped and smashed up one cylinder completely!

My money would be on water in the fuel based on what you said about water in the separator.

Check both cylinders for temperature by feel. Just in case of overheating being the trouble.
You cannot rely on the temp gauge. One cylinder can overheat while the temp gauge reads normal.

Cooling system on these is a PITA. the water supply to the aft cylinder can get cut off by blockage of the supply passage in the exhaust manifold. Cylinder jackets slowly fill with crud too. The flow out of the exhaust continues as normal via the bypass
 
Engine stopping

Thanks all. To answer the queries (for the benefit of others): There was no rope round the prop - definitely. (I have been there before, and it's a different sensation). The start is electric, the stop is by pull cable. It is working OK. I think Vic's analysis of overheating may be closest to what I experienced. We had been motoring for quite a long time (4 hrs at 1600 RPM) in gradually increasing seas, and the engine was pretty warm. I concur on the temperature gauge -it normally is all over the place for no apparent reason. I had even replaced the temperature sender, this made no difference at all.

When we eventually made our destination under sail, the engine started first turn and behaved perfectly. That was about 90 minutes later, and it would have cooled down.

Thanks again - I just need the odd £6K for a new Beta...!
 
alisdair4 said:
Two days ago we were motoring in Loch Fyne when our engine (Volvo Penta MD11c) cut out for no apparent reason. The engine had been running at about 1500 RPM for about 4 hours at that point. Fearing the worst, I hoisted sail and we made port in a professionally satisfying fashion (sailing alongside). Anyway, the engine re-started and ran satisfactorily for another 6 hours yesterday, and 4 hours today. The oil is clean; the exhaust discharges water, and so I am at a loss to know why this happened and, more importantly, if it will recur. My immediate thought was a fuel blockage, but the fuel filter seems OK.
Click to expand...

Most often air leak in the fuel system.
 
I concur on the temperature gauge -it normally is all over the place for no apparent reason. I had even replaced the temperature sender, this made no difference at all.
Click to expand...
You don't say if you have checked the thermostat but a steadily rising and falling temperature indication is I believe a symptom of clagged up water ways in the engine.

The thing to be most aware of though is the ability of the water passages in the exhaust manifold that carry cooing water to the cylinder heads to become blocked. One is longer than the other so that is the more prone to blockage. Thats the aft one IIRC.

Csail's suggestion about an air leak in the fuel system is a real possibility for the immediate past failure.
 
We had avery similar occurence a few years ago, the filters were clean and the engine ran ok for the rest of the season. Over the following winter we found a serious fuel bug infestation in the tank. With hindsight it appears that the cut out was due to a bit of crud blocking the intake, which, most likely, cleared when the engine stopped sucking fuel and was probably the first symptom of the oncoming problem. If possible I should get a fuel sample from the bottom of your tank.
 
Hi Alasdair
If a cooling way was blocked causing overheating, you may have been helped by the subsequent period of motoring being in fresh water which might have flushed the waterways, (the water in the Crinan is very slightly acid). Even though you were still outside the sea lock when you first restarted the engine, the water around the waiting pontoon is mainly fresh outflow from the lock. By the time you transit the Caley Canal the engine should have had a really good flush with very clean water.
It may be worth changing the primary fuel filter though, because if there is muck in your tank it is most likely to be a problem as the fuel level drops and when there is some turbulence like you experienced in Loch Fyne. If you can get a hand pump or a Pela down to the lowest corner of your fuel tank ( I used to take out the fuel gauge sender to do this) take out a couple of litres and have a look at it in a white container, if it is dirty take out some more until you get a clean sample. You should be able to dispose of it by putting most of it back once it is settled, dumping the residue in a milk carton. (I think there is waste oil disposal at Muirtown marina, I am not so sure about Corpach). A good beat up Loch Ness should replicate the conditions you encountered in Loch Fyne before you set off across the North Sea and you should be able to get through Loch Dochfour to berth (or anchor temporarily) under sail if the problem recurs.
 
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Is it possible that you may have starved the engine of cooling water whilst motorsailing on one tack,then changed tack so that the water intake is on the windward side of the hull and not drawing in cooling raw water. Floating crud in the tank and crushed airvent to the fuel tanks are other possibilities. Do you have a cold start button that may have not released fully?


ianat182
 
Different angle. Check that the tank breather is clear. If it's blocked, or partially blocked/kinked and warm it can suck itself shut. No air in = no fuel out. On a car/bike etc.. you check by opening the fuel cap. Not so good an idea on a deck fitting which will suck in the water/debris around itself if I'm right and there is low pressure under it.
 
Joe, thanks for that - something I hadn't considered. Certainly, touch wood, it has run a lot more smoothly since the Crinan. I last flushed it with Fernox 3 years ago - not sure how the Germans, who are real sticklers for environmentalism, will cope with that!
 
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