Replace the fuel adjusting screw (48) if it is scored or grooved.
Replace the control end (51) if it is worn at the adjusting screw (55) contact points.
Check the filter spring (59) for cracks, distortion, and mss of tension. Replace the filter spring if it is
cracked or distorted. The tension is not critical, but replace the filter spring if it will not hold the filter
element (60) against its seat, and the fuel filter cover (58) firmly against the snap ring (56) when installed.
Replace the fuel filter cover (58) if the packing groove is damaged.
Check the sleeve bearing (80) in the fuel pump housing (66) for wear. The maximum inside diameter shall
be 0.7525 inch (19.114 mm). Replace a worn sleeve bearing as follows:
Thread the sleeve bearing using a 112 inch NPT pipe tap, and install a 1/2 inch pipe plug in the
Working from the opposite side of the housing, use a hammer and punch to remove the sleeve
bearing by driving against the pipe plug.
Using an arbor press, install a new sleeve bearing flush with the face of the housing bore.
UsingST-490 reaming fixture and a 0.750 inch reamer, ream the sleeve bushing to 0.7495 to 0.7505
inch (19.037 to 19.063 mm).
Table 6-1. Fuel Pump Throttle Shaft Color Code and Class Size
Check the plunger driver (74), spacer (76), and governor plunger (77) for scoring and grooving. Check the
plunger driver (71) and plunger (73) for scoring and grooving. Replace all scored or grooved parts. If the
plunger (77 or 73) is to be replaced, select fit a new one in accordance with step (y), below.
The replacement procedure for the upper governor barrel is the same as for the lower
Check the lower governor barrel (82) for scoring or grooving. Check the upper governor barrel (83) for
scoring or grooving. If the lower or the upper governor barrel is scored or grooved, replace as follows:
Scribe a match mark across the face of the fuel pump housing (66) and lower and upper governor
barrels (82 and 83) as an aid to correct alignment of the new governor barrel.
Heat the fuel pump housing (66) in a control led heat oven to 300F (149C).
Remove the fuel pump housing (66) from the oven, and remove the lower and upper governor
barrels (82 and 83) and lower and upper spring pack housings (81 and 84) using an arbor press if
Replacement governor barrels are available in standard 1.5020 to 1.5025 inch (38.15 to 38.16
mm) diameter, and 0.010 inch (0.25 mm) or 0.020 inch (0.51 mm) oversize.
Allow the fuel pump housing (66) to cool, and measure the inside diameter of the governor barrel
bore in the fuel pump housing, and the outside diameter of the new governor barrels (82 and 83). To
allow for a press fit, the governor barrel bore in the fuel pump housing must be at least 0.002 inch
(0.05 mm) smaller than the outside diameter of the governor barrel. If the fuel pump housing bore is
oversize, line bore it for a new oversize governor barrel.