Bukh DV20 Starting Issue

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stevd

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Hi all,

So I have finally bought myself a boat. Its definitely a do-er up-er, but the main issue with the boat is that the engine wont fire.

A bit of background; the boat has stood for 3 years. I had the local boatyard mechanic look at the engine. He found it was seized, the flywheel would not turn. With a bit of persuasion he manged to free it. I am hoping this might be something simple like the waterpump rather than anything major, as it now seems to turn ok.

He then tried to fire it up, but had no joy. All that was tried was priming the fuel pump, and turning it over. When it didnt fire he also tried the decompression lever a few times and flicking it over whilst the starter motor was running.

Now that I have taken ownership I am going to try and get it going myself. Things that we didnt check was the quality of the fuel, we didnt bleed the system properly or check if there was fuel at the injectors. My thoughts are to take some new clean fuel and to try and get the engine running directly from that and bypassing the fuel filter, and bleed the system by cranking over the engine with injector cracked open a little, then tighten when there is no air left.

Can anyone suggest what else I should check / try. Please dont ommit the obvious, as I probably wont have thought about it.

I know diesels arent supposed to be run on easystart, but if I could get it firing on that, I could narrow down the problem.

Also, is it easy to adjust the decompression lever?

Thanks in advance!
 
Hi Steve
If its been seized and now rotating there may be internal problems, at least rings stuck in the pistons so no/not enough compression.
If you can get it running, (if it was a car I'd say tow it round the block several times, fast) thrash it to give it an 'Italian tune-up' which may do the trick to free up the rings.
Does it show resistance when you crank it or turn it by hand? I don't see that the decompressor adjustment if possible is an issue. Ether (easystart may help, or a flame or oil mist in the inlet while you crank NOT BOTH!:eek: )

If the refusal to turn was something else (not likely) then its back to healthy batteries and clean air free fuel-

Nick
 
stevd said:
Hi all,

Things that we didnt check was the quality of the fuel, we didnt bleed the system properly or check if there was fuel at the injectors.

Also, is it easy to adjust the decompression lever?

Thanks in advance!
Click to expand...

Go with sorting those out first. Any of the three is a 'stopper', but especially the latter two. Next in line to check would be dodgy injectors.

Err - the decompressor is either on or off (though it may be stuck in either mode).
 
Check the stop lever, or control is not in the stop position!

stuck or poorly sealing valve is highly likely as well.

also check lift pump if fitted, as it might also be stuck.
 
DV20 has stop solenoid mounted at the back of the engine near the throttle lever. If that fails to open when the engine is witched on it wont start. May be something as simple as the wire is off, or a bad connection preventing the solenoid operating?

Mine had not been run for a couple of years, and would not fire. I gave it a whiff of Easystart and it fired up. It always started perfectly afterwards. But dont use Easystart as a regular starting aid. you can seriously damage the engine.

It is important too with the Bukh that starter is turning the engine over fast enough on a cold start, or it wont fire. Again bad connections, particularly on the earth return will easily slow it down so that it will not fire.
 
What's the compression like?Can you turn the engine against compression by hand?The stop solenoid could also be malfunctioning as said.Bleed the engine as well.
 
I am pretty sure the stop solenoid fails in the on position as you can hand crank the engine to start with the electric's off in my experience, or maybe there is something dastardly clever about the electric solenoid stop.
 
The stop solenoid on a DV20 requires power to it to stop the engine. If left in the stop position, it will burn out the solenoid - I have done it, and replacement not cheap!!

As previously said, possible lack of compression due to stuck rings, injectors blocked, lift pump diaphragm split/filter clogged, valve seats burnt. All these things came to light when my VP2003 failed to start.
 
My first thought would be to open the bleed valve on the fine fuel filter and then pump the fuel pump until the diesel flows. It may even be worth taking the filter off and filling it with clean diesel before you start. I have never needed to crack open the feed to the injectors and bleed the system all the way, but that would be your next step.

My DV20 (and those of a number of other) does take a long time for the first start when it is cold. However, after a few turns it will always start with a cough or two before springing into life. Does yours cough, or just turn with no effect?

My next call would be the fuel quality. If it has been left for a few years I might expect a build up of muck. Take the mesh filter out of the lift pump (watch out for springs) and clean it all out. (does not apply to the latest type of pump). Ditto the fine fuel filter, for which I would change the element.

If still no joy, then look to the high pressure fuel pump. You need to remove the stop solenoid first - remove it with the 5 bolts on the mounting plate, and not the central nut, as this also adjusts the max engine speed. This also gives you a chance to test it and ensure it is not jammed in the stop position. When you remove the fuel pump you can check that the operating arm slides freely.

Beyond this, you will need to download the workshop manual before stripping it down.

(or, as other have said, it could be the piston rings etc...)

J
 
The Bukh DV20/DV24 are relatively simple engines and practically bullet proof however before you start pulling things off it such as the HP injection pump and Stop Solenoid get yourself a copy of the workshop manual. Section "T" is particularly useful containing as it does fault and remedy flow charts for various problems including failure to start. Other sections cover such items as correct procedure for removing the stop solenoid, correct procedure for resetting the stop solenoid etc
 
A simple(ish) diesel like the Bukh20 needs three things to start.Compression,air and fuel.The air gets compressed ,heats up and the fuel is injected and burns.First you must check compression.As I said before,if you cant turn it against compression on the handle with the decompressors down you're probably ok.Make sure the fuel is being injected and at the right time.It also should be clean and devoid of water.So bleed the system properly and check that the injectors are spraying correctly.Never put your fingers in the path of the spray because the pressure is such diesel will penetrate the skin.It can happen on engines older than 1980 that the camshaft spins on it's gear as it is not keyed(it happened to me) throwing the timing off.This is a rare but hard to diagnose fault.The valve clearances should be correct because if too small there won't be enough compression and if too large not enough air will be aspirated resulting in insufucient heating of the air for ignition.That's also not very common.If the stop solenoid is stuck in the closed position it will cut the fuel supply to the high pressure pump and the engine will not start.
On an engine that was seized I would suspect stuck rings or even a valve stuck open.
Use a well charged battery so that the starter spins the engine as fast as possible.
 
Diesels need close fitting valve seats to achieve firing compression. After 3 years laid up this may no longer be the case. Before taking off the topgear and cleaning the valve seatings, try turning over with a shot of aerosol oil to help the seating. If it fires, the heat of running will likely clear your problem. If not then its time to go to the value seats as described. This all assumes what you have said about quality clean fuel and effective lift pump etc.

PWG
 
First of all, thank you all for your quick and very helpful replies.

I still haven't started the engine, but I hope I am heading in the right direction. All though I fear I may have done something wrong after re-reading a reply.

Ok, so when I returned to the engine it was seized again, however it did free off fairly easy.

I first bleed the system as far as I could, following the fuel from the tank through the filter etc. I found that fuel was getting to the injector pump, but not past it. So, off with the injector pump, to find that all the oil in the engine has been contaminated with water, so a nice creamy mess inside. (oh well, ill sort that out after I have got the fuel sorted.) The leaver was seized but after a lot of penetrating oil, a couple of whacks it became free and loose sliding as I think it should.

Next, I found that with the stop solenoid wasnt doing anything with the ignition on. Is that correct? There was no current going to it, so I connected it directly to the battery and found that it was then moving. Possibly a corroded wire. ill look into that at a later date.

Put everything back together, bleed the system through again, and still no fuel from the injection pump :-(

Now, having re-read the replies, I am worried that I may have gotten the logic of the stop solenoid the wrong way around. My experience of diesel engines is limited to cars, so I have assumed that the stop solenoid would require a current to open it up. But now I am wondering if its the other way around, ie no current to get fuel through and a current to stop the fuel? After it was connected directly to the battery for a short-ish period the solenoid would get very warm and begin to smoke. Hence why I now think I have it the wrong way around. Can anyone advise on this?

Also, any ideas on the water issue? I am hoping it maybe a seal on the water pump or something rather than the head gasket!

Many thanks
 
Firstly don't worry about fuel etc, get the emulsified oil out and new stuff in. Leaving it could cause more damage than you want to know about. As said above several times, on the Bukh engines the stop solenoid is energised ONLY when the key is turned fully anticlockwise to the stop position and it should only be in that position long enough to stop the engine or else you will be buying a new solenoid.
I think the engine seizing is due to the moisture from the oil by the way and if so it will keep on seizing till that is sorted.
The water could be from turning the engine over with the water inlet open as this will fill the exhaust and flow back into the engine and again you will be looking at lots of beer tokens if you bend something due to trying to compress the water.
 
Last edited:
stevd said:
First of all, thank you all for your quick and very helpful replies.

I still haven't started the engine, but I hope I am heading in the right direction. All though I fear I may have done something wrong after re-reading a reply.

Ok, so when I returned to the engine it was seized again, however it did free off fairly easy.

I first bleed the system as far as I could, following the fuel from the tank through the filter etc. I found that fuel was getting to the injector pump, but not past it. So, off with the injector pump, to find that all the oil in the engine has been contaminated with water, so a nice creamy mess inside. (oh well, ill sort that out after I have got the fuel sorted.) The leaver was seized but after a lot of penetrating oil, a couple of whacks it became free and loose sliding as I think it should.

Next, I found that with the stop solenoid wasnt doing anything with the ignition on. Is that correct? There was no current going to it, so I connected it directly to the battery and found that it was then moving. Possibly a corroded wire. ill look into that at a later date.

Put everything back together, bleed the system through again, and still no fuel from the injection pump :-(

Now, having re-read the replies, I am worried that I may have gotten the logic of the stop solenoid the wrong way around. My experience of diesel engines is limited to cars, so I have assumed that the stop solenoid would require a current to open it up. But now I am wondering if its the other way around, ie no current to get fuel through and a current to stop the fuel? After it was connected directly to the battery for a short-ish period the solenoid would get very warm and begin to smoke. Hence why I now think I have it the wrong way around. Can anyone advise on this?

Also, any ideas on the water issue? I am hoping it maybe a seal on the water pump or something rather than the head gasket!

Many thanks
Click to expand...
As I said in an earlier post, GET a WORKSHOP manual before you tinker with the engine. From your description you have now burnt out the stop solenoid - there should be NO power to it from the ignition - to activate the STOP solenoid one turns the key to the upright position, pushes the key in and continues to turn the key anti clockwise - once the engine stops release the key and return it to the upright position.

If you cannot find a copy of the manual pm me with your email address and I'll send you a pdf copy - fully indexed.
The water in the oil could be from a number of different sources ranging from serious (cracked head or perforated liner) to minor (worn seals on the water pump drive shaft - easy to replace) or even condensation due to lack of running. but what ever else do not tinker with the engine any more until you have a copy of the manual and have read the relevant sections.
I hope you have not removed the injector pump as it is a ******* to refit correctly and I really hope you did not "wack" the fuel rack to get it to move cos if you did and have bent it you are looking at a new pump and many, many beer tokens.
You do not say where you are based but if you did you might find some forumite who actually knows what they are doing might offer a few hours of their time to have a look at your engine before you totally wreck it.
 
The stop solenoid does still operate, and yes I did remove the injector pump :-) . Thanks for confirming the solenoid operation, I will have another bash tomorrow.

I use the word whack, more like a gentle nudge to free it :-)

I have had a marine engineer that has condemned the engine prior to me buying it, so if I get it going its a brucey bonus.

Thanks for your help
 
It is very important that you remove the emulsified oil.As said all sorts of bad things will happen if you don't.In order for the oil to become creamy quite a lot of water must have entered the sump and you must find out where from.Do get the manual.Without it you don't know what is what.In my experience the injection pump is not hard to refit just make sure all the shims are there.They control the very crucial injection timing.This is beginning to sound quite serious and the engine should be on a bench.That creamy mess is not easy to remove.
I once worked on an engine with a holed liner and it took many hours to clean the castings because that stuff is so sticky.
 
cliff said:
The water in the oil could be from a number of different sources ranging from serious (cracked head or perforated liner) to minor (worn seals on the water pump drive shaft - easy to replace) or even condensation due to lack of running.
Click to expand...

The water pump seals are a good place to start on an old BUKH engine. There are three small tell-tale holes spaced at 120 degrees around narrow part of the pump body, and water coming out of there shows the seals have failed, but the problem is that two of the holes are obstructed by the clamp plate that holds the water pump in place and the remaining one is easily blocked up by paint and clag.
 
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