diesel leak .cold start

[jpliddy]

hi all just asking how big a job is it to fix a diesel leak on my D24 1995 im sure its coming from the cold start spindle that goes into the pump ive had a mirror under this area with a head lamp i dried the whole area last night and its wet again this morning ,its the highest point where i can see diesel leak ,
take it there a Oring behind the cold start device spindle 'how big is this job to attempt myself ?
regards jim