Is this an injection pump automatic advance device - Chinese diesel Yangong YSAD380?

[MikkiDuda]

Hi,

Nice to meet everybody, finally, through an active post.

Does anybody have any idea what this is? I have a feeling that it might be an automatic advance device for the injection pump timing, but I am not sure.

The engine is a chinese diesel, Yangdong, I think YSAD 380, and I cannot really find too much information on it. Or the information is not very clear... I guess lack of information comes with the price for these engines.

The device is attached to the injection pump timing gear. The 2 halves can slide apart during engine rotation proportional with the speed and spin the 2 eccentric circular things underneath them. The device is not present in the engine schematics I have. Those only have the injection pump gear listed.

The question arise as according to the manual, to adjust the injection timing, I should have 3 screws in elongated holes on the injection pump gear face, loosen those and turn the timing gear to get the desired values.

I only dismantle things to where they were in the last picture. Undoing the center bolt did not seem to loosen the part covering the actual gear.

Thank you.

Pictures are rotated 90 degrees counterclockwise...

[DougR]

Don't know for sure whether it's an injection timing advance or not, but it sure looks like it. If the rotation of the ecentrics change the gear position relative to the shaft position then that's what they are doing. Probably starts retarded by about 5 degrees and as soon as the engine starts to run the timing advances to its running position and stays there.

Normally done inside the injection pump, but this is a clever idea.

DougR

[a64pilot]

Originally Posted by DougR

Don't know for sure whether it's an injection timing advance or not, but it sure looks like it. If the rotation of the ecentrics change the gear position relative to the shaft position then that's what they are doing. Probably starts retarded by about 5 degrees and as soon as the engine starts to run the timing advances to its running position and stays there.



Normally done inside the injection pump, but this is a clever idea.



DougR

Aircraft magnetos have what it called an impulse coupling that changes timing for starting but also provides the fast jump needed for the magneto to make enough power at low RPM.
They are externally mounted like this.
But that devices does look a lot like centrifugal timing advance from an old fashioned distributor doesn’t it?

[MikkiDuda]

Thank you for the replies.

When I bought the boat, the previous owner told me I need to adjust the injection pump timing as the engine was running rough. After, being at my first boat, I made a beginner mistake and I managed to flood the engine with raw water and sized it. Changed all the internals (liners, pistons, valves, etc) and found a piece of old rag stuck in the air admission intake blocking air to the middle cylinder. I assumed at the moment that that would have caused the engine to run rough and the previous owner assumed the injection pump. After changing all those parts and adjusting the valves the engine started first time and run OK.
So it looks like the device is handling the timing adjustment correctly. I was somehow curios if there are any fine manual adjustments I could make.
On a short test run, during which I managed to ground the boat a bit, at full throttle - not sure the RPM as it does not have a tacho yet, boat got to 6.5 kts constant on engine.
Talk about a steep learning curve... it looks like a managed to make every mistake possible so far.

[acem]

That is most likely an advance mechanism. I have several diesel tractors on my farm but they all have the advance built into the injection pump. Thx-Ace

[Sailor 99]

Originally Posted by MikkiDuda

Talk about a steep learning curve... it looks like a managed to make every mistake possible so far.

Stuff happens. Slow down, be more careful and aware. It will get better and we have all made these mistakes.

[tkeithlu]

Amen. You think my tag line below didn't come from experience?

[dfelsent]

Don’t beat yourself up! You have made it through the shark filled academic waters.
Remember.
There are two types of sailors.
Those who have run aground.
And those who have never left the dock.