21489 Mercury SCREW, CRANKCASE TO CYLINDER BLOCK (1 3/4")

Table 1
Required Tools
Part Number Part Description Qty
5P-4150 Nozzle Testing Group 1
5P-7448 Adapter 1
6V-2170 Tube Assembly 1
8S-2270 Fuel Collector 1
1U-8857 Extension 1
6V-6068 SAE J-967 Calibration Fluid 1 Perform the following procedures in order to determine if a fuel injection nozzle does not work correctly.Bench test the fuel injection nozzles at a temperature of 18° to 20 °C (64° to 70 °F).
Run the engine at low idle.
Loosen the nut for fuel supply line at the fuel injection nozzle on cylinder number 1. Listen for the low idle to decrease or become rough. Tighten the nut for the fuel supply line on cylinder number 1. Perform this test on each cylinder.
The fuel injection nozzle is faulty when the fuel supply line is loosened and the following events occur:
The engine rpm does not decrease.
The engine does not idle roughly.Remove the fuel injection nozzle for additional testing.Note: If leakage occurs at the nut for fuel supply line , make sure that fuel supply line and the nut for fuel supply line are correctly aligned with the inlet connection of fuel injection nozzle . Do not tighten the nut for fuel supply line on the high pressure fuel line more than the recommended torque. If the nut is tightened more, the fuel line may become restricted or the threads of the fuel injection nozzle and the nut may be damaged.Cleaning of the Fuel Injection Nozzles
Before a fuel injection nozzle is tested, remove any loose carbon from the