Smokey series 2A, pump at end stop

Having a bit of a smoke problem with my 1971 2.25 diesel 2A landy, at idle there is a fair bit of grayish smoke along with a slight misfire, if I raise the idle up a fair bit with the hand throttle it runs fairly clean but dont think I will get away with setting the idle to 2000 rpm for the mot Theres also a bit of black smoke on full throttle but I'm not to worried about this. I've turned the pump round clockwise as far as it will go but think it may need to go a bit further, have pulled it out the block to see if I could shift it a tooth but it can't be done, so I'm thinking of attacking it with my die grinder and opening up the slot so it turns a bit more Is there anything else that can easily be done to advance the timing without pulling the engine to bits as there must be a fair bit of wear somewhere?? Is there any adjustment on the pump itself? Its starts fairly well and runs with no banging or knocking and it will whip the ass of my mates petrol version lol I've changed the fuel filter, set the tappets and also tried a gallon of petrol in the fuel tank but it hasn't made much difference, I've also pulled the injectors out and the faces are fairly clean and the spray patern looks consistant.
Any advice appreciated
Cheers

your prob will be a worn timing chain, not too bad to replace, if your landy is late it will have a timing mark inside the pump, there is a plate on the side with a pointer in it , you need a miror, i have cut the pump slots an it will give some improvment, but better to replace the chain, do not put petrol in this is worse than usless, i have put engine oil in the fuel on worn tractors, try it at your own risk

Sorted! No more smoke, opening up the holes done the trick. Timing chain must be well worn!