TM 10-3930-671-24 to the rear will cause compression of the governor spring (Figure 5.18). FIGURE 5.18. STEP 19 Invert the pump and holding fixture in the vise. Apply  a  light  film  of  grease  to  the  head  locating  screw. Insert the screw and thread deeply into head hand tight. Using   a   7/16’   deep   well   socket   and   torque   wrench, tighten to specification. NOTE If screw is not seated properly into the head, the seal may   be   sheared   during   tightening   (Figures   5.   19a and 5. 19b). FIGURE 5.19b. STEP  20  Install  the  cam  advance  screw  (Figure  5.20). Assemble the bristol socket cam advance screw wrench and cam advance screw bushing into the advance screw hole plug. Tighten the cam screw to the specified torque. Check cam ring for freedom of movement (locking down the  screw  can  sometimes  twist  the  cam).  If  cam  is  not free, tap the screw lightly with a brass rod. FIGURE 5.20. STEP 21 Assemble the automatic advance components (Figure  5.21a).  Install  the  piston  ring  seal  and  ring  into FIGURE 5.19a. F-243