THROTTLE PIN FOR THE FUEL CUT OFF SHAFT ON MULTIFUEL INJECTION PUMPS. 

THIS VERY TINY PIN JUST SITS IN THE END OF THE FUEL CUT OFF SHAFT ON MULTIFUEL ENGINES, IT IS NOT FASTENED IN AND IF VERY EASY TO DROP AND LOSE. 

IF YOU ARE NOT EXACTLY SURE WHERE THIS GOES, SEE THE DIAGRAM PICTURE, IT IS LETTER A, CIRCLED IN RED. 

EXTREMELY HARD PART TO FIND.