HEY ROBERT BEEN A WHILE , A 1/2 TURN EITHER DIRECTION WOULD BE PROBABLY BE TOO MUCH, THAT THING IS VERY SENSITIVE , LOOK ON THE BACK OF THE PUMP THERE IS A SMALL SCREW (BOLT) WITH A SCREWDRIVER SLOT IN IT AND A JAM NUT , 12 MM , THE SCREW STICKS STRAIGHT BACK TOWARD THE FIREWALL, IT IS BELOW WHERE THE FUEL FEED LINE GOES ON AND IS KINDA HARD TO GET TO BUT YOU CAN, I ALLMOST FORGOT YOU CAN ALLMOST STAND UP UNDER YOURS , WHEN YOU START TO ADJUST THE SCREW MARK IT SO YOU HAVE A REFERENCE POINT TO GET BACK TO , AND TURN IT SLOW , YOU DID REMOVE THE ADVANCER SPRING ALL READY RIGHT .. JERRY