Zetor 3045 - Dripping overflow pipe on Injector pump - Why?

Can anyone tell me why the overflow pipe is dripping on the injector pump?
Where is the oil coming from?
It drips when the engine is running and after for a short while.
Is it splash oil through the timing cover connection that drives the pump?
Or.. too much oil in the govenor side?
The engine occasionally revs on its own accord when ticking over, this may be linked to the same problem?

Any similar experiences and resolutions out there?

Thanks Steve

These old fasion pumps has its own oilreservoir there is a draiplugg under the pump and a fillerplugg on topp, the esie way to find oil level is unskruing the overflowpipe and fill untill oil koms out, the fluid you se komming out is a mix of diesel komming from leaking plungers and the oil in the pumps camshaft house, try an oilchage and run the engine som more and the problem migt disaper.

Hi there, You can just unscrew the top cap and fill up with normal engine oil. When filling, the diesel will keep flowing out through the drain so put a put on the ground under. Keep slowly filling until the oil you are filling comes out of the drain. Then there will be no more excess diesel in the pump. You can do this every 25 hours to keep the pump in good condition.