fuel leak? stop solenoid

[jack's lack]

i was getting nowhere with the search

im leaking fuel pretty bad seems to be coming from the top drivers side of the injection pump not where the lines come out. looks like its seeping out around the stop solenoid

i have ordered a new solenoid (thanx to bill e bob on the vortex for the link)
what size wrench fits it? (curently i only have from 8mm to 19mm and it is def bigger than the 19mm)

any other advice regarding my diagnosis, quick fixes, or personal experience with this matter would be greatly apreciated.

TIA