Got back into this one today.
Well got it out, it was in the way. Started it up 2nd pull.
Had another GV150 on a Victa base that I got from the scrap yard that had a broken rod.
Thought it might offer an answer but the carb has been messed with and had a fair whack of dirt in it, it does look clean in the fuel bowl.
Still cant work out this pilot screw.
The G150 manual says 1 5/8
The Gv100 manual says 2 3/8