lister ST3 -stamford 15kw governor issue

[Luc102]

hello everyone
Newbie to lister....
I recently purchased a genset  with a lister ST3 ....everything is in working condition..120/240 62hrtz N/L....my issue is with the governor not responding to load...the manual i have found  is of  older listers  and is  missing info for my set....also if someone could give me a build date..

the engine from what i understand seems to be presently  set at  fixed speed ..all gov. parts are in there  and free....it needs adjustment.
ive tried a few setting but no luck..it is also equiped with a fuel selenoid wich is working fine...i will include a few pics in hope someone can help me...thanks