bleeding a bukh

[robertj]

I am in the process of replacing my fuel lines on my Bukh dv 20 and would like to know if there are any quirks about the bleeding process?
has any one completely bled the whole system on this engine and know the process?

thanks

 

[Poignard]

You do it stage by stage, working 'downstream' from the lift pump to the injectors. The stages are: Lift pump to fuel filter; fuel filter to injector pump; injector pump to injectors. You have to bleed any air out of each stage before moving on to the next.

First slightly loosen the bleed screw on the filter mounted on the engine and operate the lever on the lift pump until just fuel without air bubbles appears. Re-tighten the bleed screw

Then slightly loosen the bleed screw on the injector pump and turn the engine over with the starting handle or starter until just fuel without air bubbles appears. Re-tighten the bleed screw. (nb if doing this afloat, shut the cooling water seacock so you don't fill up the exhaust sytem with water, which might otherwise get back into the cylinders).

Finally slightly loosen each injector coupling nut in turn and turn the engine over until just fuel and no air comes out. Re-tighten the coupling.

Re-open the seacock and start the engine.

 

[skipklaus]

There is no need for bleeding. I started my DV20 after general maintenance and 10-15 seconds with the starter he came back to life.

 

[30boat]

There is no need for bleeding. I started my DV20 after general maintenance and 10-15 seconds with the starter he came back to life.

I'd say you were lucky.These are not self bleeding engines.It should be done as explained by Parsifal.

 

[conolan]

Never bled

I've never bled my Bukh 10 (31 years old) because it didn't need it. The tank is above the engine so gravity feeds it.
HOWEVER, this week engine stopped and wouldn't restart. Traced problem to blockage between tank and valve before primary filter. Blew back the line and fuel flowed. Fuel also flowed at secondary filter (which was still off). But the engine wouldn't re-start. Then tried bleeding at secondary filter and before injector pump. Full flow immediately. However still won't start, not a kick out of it.

To reiterate, any time I've removed filters never had to bleed because engine starts within 3-4 seconds, as per normal. Also engine hasn't been smoking, sounding rough or anything out of sorts.

 

[cimo]

I always imagined not designed as self bleeding, but i never had to bleed my 20 to date (well not in the 10 months I've had it so far).

not sure if it's standard, but my 20 has fuel return lines at both injectors and at the secondary fuel filter also. This & sufficient cranking appears to take care of any air in the fuel feed. I have seen air in the line between primary filter and lift pump, but it never causes a problem - getting shunted back to the tank at the secondary filter i imagine. Perhaps the 10 is different?

hello conolan - from what you say your engine appears to be getting fuel. Could your starting issue be down to blocked air intake or poor compression perhaps?

 

[Alcyone]

I've found the lever on the fuel lift pump on my dv10 brilliantly ineffective in pulling fuel through to that pump after filter change etc. I use a sump pump to get it to the fuel lift pump, and use that to prime to the second filter and engine itself.

 

[Gin]

I am in the process of replacing my fuel lines on my Bukh dv 20 and would like to know if there are any quirks about the bleeding process?
has any one completely bled the whole system on this engine and know the process?

thanks

After I had changed my primary and secondary fuel filters this year I was unable to operate the lift pump as the wretched sprung handle dropped off the underside of the pump and I couldn't(still cannot refit it). So I cracked open the injector union, decompressed the engine and manually rotated the flywheel with the starter handle until fuel appeared- worked a treat

 

[robertj]

Thanks all will sort it soon.
Is there any manual that will rake me through each step and where each bleed screw is ect?
Bob