Runaway engine on the Thames

kingfisher

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A real life what-now-skipper scenario, I'm afraid.

I usually reside on the other forum (the rag 'n stick bunch), but since this is engine related, I'm posting it here.

We just spent 5 days enjoying the hospitality of St-Kaths and everything that London has to offer. But holidays must come to an end and we set off on wednesday morning with the outgoing tide. We are already 1 hour past the Tidal Barrier as I realise that I had forgotten to check the oil level of the engine. I remove the dip stick and it is completele dry. I ask my wife to turn off the engine, and pass me the oil. I pour in a generous amount of oil (about half a liter, which is half of what a VP2001 takes) and we restart the engine. I check the level, and notice that the oil level is all the way up the stick, waaaay past the marker.

Pheh, this thing drinks oil anyway, so we (I) decide to carry on. 10 minutes later, all of a sudden the engine revs go up. First reaction is, someone bumped the lever. But putting the lever back doesn't do anything, in fact the revs keep going up. Handle to neutral, nothing. Estelle tries to kill the engine by pulling the stop button. NOthing. By now the thing is going full tilt (it is in neutral). I realise that it must be feeding off the oil. The white smoke (closest to a ferrari f1 blowing a gasket I ever came) is billowing behind the boat.

I decide there is nothing much I can do, so Estelle and I take refuge on the front deck, waiting for the engine to die out/run itself to bits/blow up in spectacular fashion. Luckily a motor boat was a few hundred meters a way, and they quickly came to our aid. Not that they could do much, but it was a great feeling, not being there on our own. After about 8 minutes of full revs, the engine slowed down and died. I radioed London VTS, there was a bit of a caffufle to detail our position, but that was quickly resolved.

The good news is that after a bit of cooling, the engine started again, and everything is fine (fuel pump, water pump, alternator). So the only result is a few liters of burnt oil, I'll do an oil and filter change ASAP.

We met our stand-by boat again in Ramsgate, I gladly gave them a bottle of Californian chablis. I would have liked it to be a better present, but it was the best bottle on board.

So: alternate scenarios, solutions, things to check on the boat now? I think I could have blocked off the air intake, but that would have required crawling under the nav table, opening a hatch behind the runaway engine, and blocking the air intake nozzle. Frankly, I prefered the safety of the foredeck.
 
A real life what-now-skipper scenario, I'm afraid.

I usually reside on the other forum (the rag 'n stick bunch), but since this is engine related, I'm posting it here.

.......Pheh, this thing drinks oil anyway,........, all of a sudden the engine revs go up. First reaction is, someone bumped the lever. But putting the lever back doesn't do anything, in fact the revs keep going up. Handle to neutral, nothing. Estelle tries to kill the engine by pulling the stop button. NOthing. .....

I decide there is nothing much I can do, so Estelle and I take refuge on the front deck, waiting for the engine to die out/run itself to bits/blow up in spectacular fashion. ......

The good news is that after a bit of cooling, the engine started again, and everything is fine (fuel pump, water pump, alternator). So the only result is a few liters of burnt oil, I'll do an oil and filter change ASAP......

...... I think I could have blocked off the air intake, but that would have required crawling under the nav table, opening a hatch behind the runaway engine, and blocking the air intake nozzle. Frankly, I prefered the safety of the foredeck.

First of all, you did the right thing to seek refuge as you had no safe way of blocking the air intake (the best way to stop a runaway engine)!! Better the engine blowing up than having people hurt...

Anyway a few things .... if an engine "drinks" oil, it is an indication that the oil is going somewhere... that somewhere is usually into the combustion chamber through worn piston rings ... and when piston rings are suitably worn, or cylinder is damaged, it is not a question IF you'll get a runaway engine .... it is WHEN... so this will in all probability happen to you again ...sooner or later unless you get the engine checked over properly !!(compression test will give a quick indication if you really have a big £££ problem).

Not wanting to be all doom, but please do not assume that oil & filter change will magically "fix" this one for you..
 
You don't say which engine this is but I would advise doing anything to shut off a runaway diesel engine. It is quite feasable for them to drop a con rod throgh the sump, which would most likely continue on through the hull.

A balled up rag in the intake or a sheet of paper (chart) over it will work fine and be quite safe.
 
As said, it is a 1993 Volvo Pënta 2001. I had the engine revised last year, it actually went out of the boat.

One question: I thought the black T-shaped plastic that one pulls to shut of the engine, is actually a decompression lever. So why did the engine not stop when my wife pulled it?

Second question: When I open the oil reservoir lid, when the engine is running, I feel pulsating air. Should this be the case?
 
or a C02 extinguisher, not powder !

A relatively small 1 litre, (four stroke) engine sucks in 1 litre of air every 2nd RPM (Power stroke, then air charge stroke) ... Runaway engine at 2000 RPM = 1000 L every minute

Take a CO2, 2 Litre with gas at 55 bar (anyone carrying bigger ones?), that gives 110L of gas, discharged in 8 seconds = 13.75 L per second (ref manufaturers spec.)

Engine require 1000 L per min = 15 L required per second .... so you have a defecit in both the discharge time and limitations in discharge volume.... (so air will be sucked in) .. Bigger engine = bigger problem)..

Net result is that you have slowed the engine down for a couple of seconds, and have risked your health and may have reduced your fire fighting capabilities, which you may need later.

I still say that OP took the correct actions under the circumstances...
 
As said, it is a 1993 Volvo Pënta 2001. I had the engine revised last year, it actually went out of the boat.

One question: I thought the black T-shaped plastic that one pulls to shut of the engine, is actually a decompression lever. So why did the engine not stop when my wife pulled it?

Second question: When I open the oil reservoir lid, when the engine is running, I feel pulsating air. Should this be the case?

There is "Revised/Re-built" ... then there is "Re-builds". Some people say "Re-build" when they mean major services such as injectors etc.

A proper re-build in effect re-builds the engine to within the manufacturers tolerances etc., so will have had the engine split, pistons out, pistion rings checked/replaced... etc., basically all moving parts checked and replaced as required by the manufaturers spec.

The "STOP" leaver is usually a fuel cut off... in this case you were running on the lube oil, so that the engine only stopped when it ran out of lube oil,... you had already stopped the diesel flow with the leaver.

Sounds like you may have some crankcase pressure (some is normal), but it may be a result of compressed air being forced into the crankcase as a result of worn/cracked piston compression rings (which would explain where the engine got the oil to burn from).

I would have done a compression test to lay my mind at rest if it was my engine..
 
One question: I thought the black T-shaped plastic that one pulls to shut of the engine, is actually a decompression lever. So why did the engine not stop when my wife pulled it?

That's not a decompression lever. I suggest you get hold of the manual. If you Google it you'll find a shoddy scanned PDF which will at least show you what the decompression lever looks like.
 
As said, it is a 1993 Volvo Pënta 2001. I had the engine revised last year, it actually went out of the boat.

One question: I thought the black T-shaped plastic that one pulls to shut of the engine, is actually a decompression lever. So why did the engine not stop when my wife pulled it?

Second question: When I open the oil reservoir lid, when the engine is running, I feel pulsating air. Should this be the case?

Sorry missed the Eng spec earlier. The decompression lever would have to held it off until the engine stopped or it would just restart again with rotary momentum. So maybe the wife didnt keep on pulling...

If there is pulsating air coming from the oil resevoir then you have some kind of compression leakage. It's normal to have some on an old engine. I agree that you should get a compression test done.

Hope it works out.
 
If there is pulsating air coming from the oil resevoir then you have some kind of compression leakage. It's normal to have some on an old engine. I agree that you should get a compression test done.


Not thought that its a single cylinder with one lump bouncing up and down?
 
Sorry missed the Eng spec earlier. The decompression lever would have to held it off until the engine stopped or it would just restart again with rotary momentum. So maybe the wife didnt keep on pulling..........

Nope .. the wife did everything right ... stop function on this engine is part of fuel system ... (http://www.volvo.com/NR/rdonlyres/60BB162C-A8F2-4D0C-BC1D-0421BD4F3BBC/0/2001_MS2B_120B_1988_en.pdf ).

The lady shut off fuel, but engine was running on lubrication oil which could not be restricted in this way. Only other option is to restrict air flow to stop another element required for combustion.

Very few engine manufaturers fit a air shield as standard, but is in principle easy to install and will provide another way to stop the engine in addition to fuel starvation which in this case would not have helped..
 
As said, it is a 1993 Volvo Pënta 2001. .....

Second question: When I open the oil reservoir lid, when the engine is running, I feel pulsating air. Should this be the case?

As it is a single cylinder engine, the crankcase volume increases as the cylinder volume decreases, and vice-versa, so yes, it is normal. All single cylinder engines have a breather arrangement to prevent excessive crankcase compression. Make sure yours is not blocked as a blocked breather increases the chances of lubricant passing the piston rings or being forced down valve guides.

As to your main problem, the cause is oil either passing into the cylinder via worn piston rings and or cylinder bore, or down the valve guides, or both. Cylinder/ring wear is the most likely culprit. This needs to be sorted out, or the engine will run away again. Overfilling is a guaranteed runaway in a worn engine.
If the engine has a decompression lever make sure you know how to find and operate it. It is a sure fire engine stopper.
 
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I found a pdf engine manual here. http://members.dslextreme.com/users/j40ed/volvo_penta_2002_worksh.pdf To my surprise oversize pistons are available, so serious bore wear can be dealt with by a rebore and new piston and rings. The oversizes are very small, and considerable skill would be needed to set up accurately enough to bore oversize by only 0.25mm.

P.S. I wonder if the rebore is actually done with a special expanding reamer followed by a cylinder hone?
 
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A real life what-now-skipper scenario, I'm afraid.

I usually reside on the other forum (the rag 'n stick bunch), but since this is engine related, I'm posting it here.

We just spent 5 days enjoying the hospitality of St-Kaths and everything that London has to offer. But holidays must come to an end and we set off on wednesday morning with the outgoing tide. We are already 1 hour past the Tidal Barrier as I realise that I had forgotten to check the oil level of the engine. I remove the dip stick and it is completele dry. I ask my wife to turn off the engine,


Mistake to dip engine when running. You will get a different reading from when stopped and overfill unless you check when stopped....Next time check the oil depth AFTER STOPPING!!!!! The result is what normally happens if you overfill a slightly worn diesel.

The stop button on a volvo closes the fuel off at the fuel pump and this would have no effect in your case as the governor has already done this. Sometimes it is safer to leave the engine in gear and so reduce the energy available for sending bits of flywheel and con rod through the bottom of the boat. In your case the decompressor would have stopped the engine . This is a small toggle lever on the rocker box however I believe this might have been omitted from some 2000 series engines.

Always dip the sump under the same conditions to get consistant readings.
 
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