Bukh engine slow to start

[JimC]

My Bukh 20hp seems to take more cranking than it used to before it starts, first one cylinder cutting in, then the second. Once going it runs perfectly and ,if restarted within a few hours of having run, it starts immediately. Left overnight or longer it needs lengthy cranking again. When running it makes a small amount of grey smoke, not much, and never black.

I've changed the pre-filter and engine fuel filter and cleaned the little gauze in the top of the fuel pump. I've bled the system and, when I slacken an injector nut and crank the engine, fuel issues from the loosened connection like it should do.

Any Ideas ?

 

[Footpad]

Have you fitted a preheater - sorted out our poor starting beautifully.

 

[philip_stevens]

Just maybe, the injectors need servicing?

As said above, an inlet heater will improve starting. I fitted one to my Bukh on my previous boat.

 

[Evadne]

If there's air in it whenever you bleed it, then that's your problem. Can be caused by pinholes in the fuel line, slack joints etc., and indicated by dripping fuel.
If fuel is geting in but it's not burning then my thoughts are: compression failing (rings or bore glazing), not enough fuel getting there for cold starting (fuel pump diapragms) or that the injectors are on the way out. If you are getting smoke when running warmed up, this may be a pointer, unless it has always done this. Getting them serviced may be a good thing if not done in the near past anyway.

 

[Colvic Watson]

You can also hand crank 3 or 4 revs with the decrompression level down which I was told by Bukh was a cure for cold start problems. These engines are pretty much bombproof and I would recommend calling Bukh as they are far and away the most helpful marine firm on the planet.

 

[asj1]

It would be worthwhile getting the injectors out and serviced - I took mine to a specialist truck servicing company. Getting the injectors out is not difficult providing you have the correct very large sockets - one of which I seem to recall needs to be deep. Bukh will tell you what tools you need and sell you the new washers etc.

 

[Gin]

Speak to the nice people at Bukh,01202668840 and they will confirm that cold starting is a well known problem with Bukh's and their cold starting kit (about £145 for my DV10)will transform the starting problem immediately .

Just bought the kit for my lightly used but 1991 engine and it is a very simple diy job.

 

[VicMallows]

Gin,

Does the kit you fitted comprise an electric heater element in the inlet manifold, or does it use a 'Thermo-start' plug with a diesel feed (electrically ignited)?

I agree BUKHs without heaters are near impossible to start below about 2degC! ... mine was even when new. An option I used to use is a hose from the Eberspacher onto the air inlet for several minutes......but these days the Eber won't start unless the engine is running /forums/images/graemlins/frown.gif

Vic

 

[jerryat]

Agree with others about getting the injectors serviced, especially if this hasn't been done for a few years.

I fitted a 'cold start' heating unit kit in the inlet manifold of my 20hp version a few years ago 'cos the engine seemed slow to start, but in reality I don't hink we've used it more than a dozen times in as many years.

As mentioned, they do tend to be slowish starters, and a 5-10 second burst on the starter seems to be the norm for us following a period of non-use (a few days), but thereafter it starts within 5 seconds - until the next non-use period.

We don't even think about it now as it's just the way it is, causes no problems, and the engines are so utterly reliable.

Must just second Pasta Simon's comments re the helpfulness of Bukh Diesel UK. Superb company run by a couple of extraordinarily knowledgable people.

 

[marcusgillies]

is the starter getting tired?

 

[jerryat]

Don't know if you intended to reply to me 'cos I definitely have no problems with the engine - I've just stripped it down and fitted new liners, pistons, rings, ends, pump etc etc - and it runs like a sewing machine. /forums/images/graemlins/smile.gif /forums/images/graemlins/smile.gif

It does take a couple of seconds longer to start in this very cold weather, but when I feel the new compression brought about by fitting the new parts, compared to the old, I'm surprised it doesn't take even longer! It's seriously high compression now that's for sure!!! /forums/images/graemlins/shocked.gif /forums/images/graemlins/smile.gif /forums/images/graemlins/smile.gif

Starter motor's fine. /forums/images/graemlins/smile.gif

 

[cerro]

The best way to start a bukh engine from cold is with an Oil can two squrts down the air intake and she starts first time every time cerro

 

[pampas]

Cerro is right but the cause is the rings wearing and the oil scraper not retaining enough oil for the initial start (Cold)

 

[Blueboatman]

OK You've all sorted the cure,now the thread drift.
When I had a Sabb diesel-and was a diesel novice-there was a tin of mysterious 'cigarette butts' that you could insert into a special threaded cavity on the side of the cylinder,in really cold weather,according to the manual..I never figured out what they were or what they did,cos..(back to thread)I used to wind it over several times decompressed when really cold,to get the oil up to the rings,then it started easily

 

[Robin]

Scandinavians always did like the odd funny rollups to get them going.

 

[JimC]

Thanks everyone for your advice. It seems that slow starting is to be expected in cold weather but, if it persists, I should get my injectors serviced - which I will. Thanks again.

 

[cliff]

One other point to note is the tick over speed setting.

If the tick over setting is too low the engine will take forever to start. These engines start on "full throttle" irrespective of where the teleflex control is set then as the engine fires cuts back to tickover and stalls if the tick over is too low and the engine is cold.
Simple test is to open the throttle a little using the teleflex control and try starting. If this works you need to reset the tickover control.

Been there, done that and got the scars......
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"Artificial intelligence is no match for natural stupidity"

 

[mercman]

ask for norman at bukh always helpful....what is the compressions like when you turn the engine over by hand on the flywheel..
we regularly removing heads on older engines and re lapping etc worth a look

 

[vyv_cox]

Injectors might be a problem but my opinion is that poor compression is the more likely cause of poor starting in colder weather. If compression is perfect the heat of compression is sufficient to take the fuel over its auto-ignition temperature in a very short time. If some compression is escaping down the rings or past the valves it will take longer to reach the autoignition temperature. For reference, I had a Bukh 20 in my boat that always started first turn of the key, summer and winter.

It's easy to check whether this is the cause. Squirting a little oil in with the air seals some of the gaps at the rings. Next time you cold start do this and see if it solves the problem. Air passing the valves is not so easy to detect but you can sometimes hear this happening. Make sure your valve clearances are correct.

 

[cliff]

[ QUOTE ]
ask for norman at bukh always helpful

[/ QUOTE ]I did, and it was he himself who tipped me off as to the cause of the sluggish starting on my DV24. /forums/images/graemlins/grin.gif
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"Artificial intelligence is no match for natural stupidity"