TM 9-2910-226-34 f. Connect outlet of the nozzle tester to the im- provised adapter using a high pressure hose. g. Install locally fabricated U tube in the No. 1 hydraulic head outlet. Position a plastic container under the open end of the U tube to collect test oil (which will be returned to the tester reservoir) (fig. 3- 164). h. Remove timing device cover and timing window cover, or fuel shutoff housing. 3-53. Hydraulic Head Port Closing Test. a. Secure the throttle lever in the full fuel position with a spring or other suitable device (fig. 3-163). b. Remove delivery valve screw (A, fig. 3-166) and delivery valve spring (B). Reinstall delivery valve screw. NOTE Delivery valve is matched to the hydraulic head. Do not replace or interchange valve. c. Apply 3-10 psi test oil pressure to the hydraulic head with the nozzle tester. Loosen the ΒΌ in, pipe plug in the hydraulic head overflow valve opening to bleed air from the head. Tighten plug. d. Rotate the test stand drive coupling clockwise (as viewed from the drive end) with the test stand spanner wrench until the slotted, red painted tooth is visible in the timing window on the pump housing (fig. 3-167). A Delivery valve screw B Delivery valve spring C Fuel delivery valve Figure 3-166. Installing fuel delivery valve and screw. Figure 3-167. Alining slotted tooth with arrow on housing. NOTE The scribed mark on the advance unit hub should not be alined with its pointer, e. Slowly continue to rotate the drive hub in a clockwise direction (as viewed from the drive end) until the test oil begins to form droplets at the end of the U-tube. Slowly continue to rotate the drive hub until the test oil flows freely and then diminishes and stops. This is port closing. The scribed mark on the advance unit hub should now be alined with the pointer (fig. 3-168) and the slotted, red painted tooth in the timing window should be one tooth to the right of the mark on the pump housing. If the above specification is not met, the hydraulic head, tappet assembly and/or camshaft must be replaced. If the plunger button is damaged, hydraulic head must be replaced. f. Install the timing device cover using a new gasket, and tighten the retaining bolts and lock- washers fingertight. Install timing window cover or fuel shutoff housing. Remove U-tube from hydraulic head (fig. 3-164). Remove delivery valve screw (A, fig. 3-166). Remove fuel delivery valve (C), and 3-97