Bleeding a Bukh

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KenMcCulloch

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I have to service a 3 cylinder Bukh (DV36) shortly. The manual advises that the filter should be bled and then the injectors - no facility for bleeding at the injection pump. Has anyone with Bukh experience any advice on this, do I do the injectors one at a time, and in what order (does it matter?) or do I crack them all open at once and tighten them in turn once the bubbles are done? There are a number of possible permutations.

Oh and another thing. There is a drain screw or somesuch on the bottom of the Bukh fuel filter. What's that all about?

Informed responses welcome.

Cheers
 
Don't think there's a bleed screw on my Yanmar fuel pump either. I could be wrong on that, but fairly sure I just bleed at the filter (on the engine) and at the injectors. I generally do them one at a time, while swinging the engine by hand.

Presumably the screw on the filter bowl is for draining water?

Pete
 
Not sure if it's the correct way but it works for me! It also assumes your batteries are in fair condition! If I need to bleed my Bukh 24 I simply turn on the fuel supply, check there are no obvious leaks at the filter housings, free off a single injector and turn the engine on the key until fuel escapes from the freed off injector. Almost simultaneously the second cylinder will fire and the engine runs roughly, i let it run for maybe 5 seconds or so before tightening up the freed off injector at which point the engine runs properly. I then recheck for leaks around the fuel filters.

In other words the DV24 (2 cylinder) is pretty much self priming and self bleeding. I imagine the 3 cylinder jobbies are much the same?

Cheers, Brian.
 
I have a DV10 and I 've never had to bleed the injector.
I bleed at the fuel filter, then turn it over on the starter and decompressor.

Its only a single cylinder, so I cant "run it rough" on one till it runs through as flobbergob does, but the fact that it self primes with one cylinder suggests it would for 2 or 3 too, so I don't think flobbergob has to even open one injector, just turn it over once theres fuel at the filter.


ps I don't think theres a drain on my fuel filter, It's a bowl around an element, secured from the top.
 
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The 20 appears to be very tolerent of air. Sufficent cranking seems to do the job. My procedure is to bleed just enough to reduce the cranking time. But sorry, not 36 specific.
 
I replaced the fuel filters on my DV10 a couple of days ago and just released the bleed screw on the filter mounted on the engine while I primed the filter bowl using the lift pump lever. When fuel came out of the bleed screw without air bubbles I tightened it. Then started the engine with the starting handle. No problems at all.

The only time I have bled the injector pump and high presure pipe was after having the pump and injector serviced. Even then it may not have been necessary because I think the engine is supposed to be self-bleeding.
 
KenMcCulloch said:
I have to service a 3 cylinder Bukh (DV36) shortly. The manual advises that the filter should be bled and then the injectors - no facility for bleeding at the injection pump. Has anyone with Bukh experience any advice on this, do I do the injectors one at a time, and in what order (does it matter?) or do I crack them all open at once and tighten them in turn once the bubbles are done? There are a number of possible permutations.

Oh and another thing. There is a drain screw or somesuch on the bottom of the Bukh fuel filter. What's that all about?

Informed responses welcome.

Cheers
Click to expand...

My Fuel filter is a Bosch wih a drain screw at the bottom posibly same as yours. After changing and filling with clean fuel undo vent on filter (slotted scew) then actuate manual lift pump to clear air, then loosen pipes on injectors, As I am right handed I usually start at the front and work back making it easier to use my left hand for the spanner, and my right for the lift.
 
KenMcCulloch said:
I have to service a 3 cylinder Bukh (DV36) shortly. The manual advises that the filter should be bled
Click to expand...

Going by my experience with a Bukh 20, you need only bleed at the fuel filter after replacing it. Use the lever on the side of the lift pump to pump the fuel through, but make sure it's off the cam or it will take an age. If you've got a problem further down the line, crack off the connectors to the the injectors. I'd do this one at a time. But you shouldn't need to do this if you haven't disturbed the pipework from the filter to the injection pump and to the injectors.
 
KenMcCulloch said:
I have to service a 3 cylinder Bukh (DV36) shortly. The manual advises that the filter should be bled and then the injectors - no facility for bleeding at the injection pump. Has anyone with Bukh experience any advice on this, do I do the injectors one at a time, and in what order (does it matter?) or do I crack them all open at once and tighten them in turn once the bubbles are done? There are a number of possible permutations.

Oh and another thing. There is a drain screw or somesuch on the bottom of the Bukh fuel filter. What's that all about?

Informed responses welcome.

Cheers
Click to expand...

Is there a screw on the side of the discharge ports??? It is the same pump as the MD2 usually and there a screw .

The injectors can be bled one at a time or all together, it is your choice. Just wait for air bubbles to give way to fuel and tighten the big nut.

The tap on the bottom of the filter is for draining water.

If you didn t have that indecently high bridge deck I d pop over with a shifter.

:D:D
 
Thanks for all the replies. I now know that I was correct in guessing that the filter has a water drain (though if water had got that far past all the other traps and filters I would be seriously worried) and that it doesn't matter much which order to bleed the injectors, and indeed if I am lucky little or no air might be expected to pass into the HP end.

Cheers
 
From the DV36 workshop manual
After changing the filter bleed the fuel system by actuating the manual handle on the fuel lift pump and pump until the fuel, free from air bubbles, runs out at the vent screw on the top of the fuel filter. Tighten the screw and loosen the fuel pressure pipes at their connection on the fuel valves and pump again with the fuel lift pump until fuel, free from bubbles, runs out from the fuel pressure pipes.
Click to expand...
- simples....
 
Digger F said:
cliff said:
From the DV36 workshop manual - simples....[/QUOte
Yep, I have the same manual but it is a pity that other replies have been quoting DV 20 etc when the original thread stated DV36 which I have on board (plus a spare)
Click to expand...

in fairness to those who posted after you D, you didn't mention 36 in your earlier post. Interesting enough thread nonetheless.

it may be of further interest to some -
do you find you have to fully follow the manual's procedure as describe for the 36, or is it your experience that you can get away with just bleeding at the secondary filter (per the 2 cylinder 20 for example).
Click to expand...
 
Digger F said:
cliff said:
From the DV36 workshop manual - simples....[/QUOte
Yep, I have the same manual but it is a pity that other replies have been quoting DV 20 etc when the original thread stated DV36 which I have on board (plus a spare)
Click to expand...

We all have experience of the Bukh engines we have. I think all of the replies have implied the 36 is not different in respect if the bleeding process. Without those replies it would have been a spectacularly silent thread.
Click to expand...
 
chewi said:
Digger F said:
We all have experience of the Bukh engines we have. I think all of the replies have implied the 36 is not different in respect if the bleeding process. Without those replies it would have been a spectacularly silent thread.
Click to expand...
You will doubtless then be aware that the fuel delivery system on the DV36 is quite different from that on the DV20/24 and the DV10. OP stated DV36 and the relevant section of the manual was quoted. Bleeding the DV36 is relatively simple though bleeding the HP lines to the injectors is often required whereas bleeding the HP lines on the DV20/24 is seldom required.
Click to expand...
 
Well, we didn't get round to doing the filters before lifting out so decided to leave it until she was afloat. Getting the primary filter to fill up was a bit of a bugger but eventually solved by raising the level in the main tank above the height of the filter. The fine filter on the engine was a doddle and no bleeding of injectors was required.
 
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