A Bukh DV10 puzzle

[morgandlm]

My Sadler 26 has the original Bukh DV10 which has been well looked after and had never let me down. Last Sunday I enjoyed a weekend cruise which involved several uses of the engine without any problem. For the return to the marina I had started the engine and motored for about 15 minutes to get to my pontoon berth. All the foregoing was perfectly normal. However, about 50 metres short of my berth the engine simply slowed and stopped as if run out of fuel. The tank was half full and the supply valve open.

I subsequently checked the filters and changed the secondary, spin on fuel filter although the one in use was only a few months old. No evidence of dirt or water was found. I bled the system and eventually got the engine to start but it was very reluctant – firing but not sustaining itself. It eventually started but only runs very slowly and will not speed up when throttled up. My feeling is that there is a problem in the injector pump / governor system but do not know enough about how this works. This latter would perhaps explain the not speeding up but I do not see how it would explain the coming to a stop when running perfectly.

I would be most grateful for any suggestions or possible diagnosis.

By the way I was very luckily able to drift to the end of my finger pontoon, catch a cleat and with some help from the shore, berth the boat. A dry mouth moment!

David Morgan

 

[Poignard]

I think I'd still be tempted to suspect contaminated fuel before shelling out money on anything else.

You could eliminate that as a possibility by running the engine with clean diesel from a bucket or can.

 

[chewi]

I had this with my DV10 . it spoiled 2 seasons knowing that it would die like that. It would run OK for hours, but after about an hour it would no longer tick over. Eventually I repowered (beta 20, smaller lighter smoother). The only part of the engine I didn't dismantle to diagnose was the thermostat housing, which implies it was overheating, but it didn't alarm and I have only had that enigine for 22 years so I was used to whatever temp it got to so it might have been too hot.

 

[neilf39]

Have you used a dinghy pump to blow back through the fuel lines? You could have a bit of crud in the pipe which is severely restricting the fuel flow. Feed the engine direct from a pipe dipped in a fuel container to see if that helps. Alternate is the exhaust is almost blocked, could be a bit of the flexible pipe has collapsed on the inner layers or the exhaust elbow has finally blocked enough to restrict the engine.

 

[morgandlm]

Thanks for all the ideas. I have now exhausted all the possible fuel supply related doubts. The problem appears to be with the injector pump system where I believe there is a governor and a fairly complex mechanism. Access to this is next to impossible in a Sadler 26, so it means engine out. Before taking this drastic step can anyone with experience of Bukh engines suggest what the failure could be. The engine will start but only runs at very slow idle (slower than normal) and does not do the normal pick up to the usual idle speed.. In the past it was occasionally a bit slow to do this but it always got going after a few seconds ... now it doesn't. Opening and closing the throttle makes no difference. What is in there than can "stick" or seize?

David Morgan

 

[Poignard]

Have you checked that the arm that the throttle cable is attached to is not slipping on the shaft it is clamped to? I'm thinking if the pinch bolt/nut was loose, or could not be tightened due to stripped threads....

Just a thought...

 

[Boater Sam]

Stop cable not fully home?

 

[jwfrary]

If the cable is working as it should then could be that the rack is sized in position stuck and therefore the fueling doesn't increase in volume and therefore engine doesn't increase in speed. I'f this is the case and the arm still moves something in the mechanism has failed.

That said the most likely cause is something simple, fuel or air supply related rather than the reletivly reliable govener mechanism

 

[Robin]

Years ago we had Bukh 10 that had a sticky injection rack was fine until slowed when it could shut down unexpectedly restarting needed a thump encouragement like engaging gear under sail like a bump start for a car or using the decompressor lever whilst running starter. Not useful 50 yds off a berth mind. Our problem vanished after a new camshaft required a rebuid

 

[vyv_cox]

The symptoms appear to indicate a fuel supply problem. The injector pump would not be my first suspect as there is not much in there that would change suddenly. Have you looked at the lift pump? I suggest you work forward from the tank checking flows. Take the inlet hose off the pump to ensure fuel flows out at a good rate. Then take off the discharge hose and turn the engine over, checking flow rate. Robin's post suggests that maybe the eccentric cam driving the pump had worn?