Thanks Diesel911.

I have 98 E300TD. Does it have M-W pump?

That pin is exactly what I am talking about. Do you think I got it right, to adjust the pin from side of the pump? If you have a picture of what it will look like when I open that metal plate? I have never done it so, just want to get better idea and prepare before hand. also my view will not be that great with the pump in the car with shut off valve blocking view etc...

Someone recommended not to remove the shut off valve from the pump, he said that will cause lot of work...but said to remove the fuel pump if need be. are they easy steps?

Also, The whole thing started with me mistakenly lifting the barrel out of the pump. and the pump not working correctly after that for obvious reasons...that is, the barrel did not get aligned correctly with the plunger when I put it back in. I think when I lock that pin again to the barrel, the barrel and plunger will be back in correct position. Any further calibration needed after that or the pump will be running as it run before I started to change the ORings....

Thanks,