16123 Mercury SCREW (LONG)

Fuel System
Cold Start Heater Tests
Basic Checks
Cold Start HeaterA characteristic of the cold start heater is that the heater coil often appears wet. This happens because the diesel fuel does not burn completely, and has the appearance that leakage exists. This condition is normal and should not be taken as an indication the ball valve has fuel leakage. If necessary, do the Leakage Test.Check the heater operation by checking that the inlet manifold is warm to the touch near the heater after approximately ten seconds of operation.Check that the fuel tank and fuel lines to the heater unit do not have leakage of fuel.Check fuel shutoff valve for correct operation. A poor seal can cause air to enter the system which will cause extra cranking of the engine before starting. Be sure all fuel connections are tight and not leaking air.Be sure the battery condition and state of charge is satisfactory, and all electrical connections are tight. A discharged battery or loose connection can cause reduced voltage and starter motor terminals (slow cranking) or failure of heater unit to be activated.
Do not crank the engine for more than 30 seconds. If the engine fails to start, allow the starter motor to cool for two minutes before attempting to start the engine again.
Leakage Test
Remove the cold start heater from the inlet manifold. Connect an air supply of 140 kPa (20 psi) maximum to the fuel inlet passage.
Do not use air with more pressure than 140 kPa (20 psi) or damage can be caused to the heating element.
Put the cold start heater in a container of clean diesel fuel for ten seconds. No air bubbles should be visible from the cold start heater.If a leakage is shown, install a new cold start heater. Remove the fuel from the cold start heater after the test.Electrical Test
1. Connect the clamp lead of a 6V7070 Multimeter around the wire at the cold start heater.2. Activate the cold start heater switch.3. The tester must indicate correct electrical continuity and connections to the unit.4. To check the current draw, put an 8T0900 Clamp-On Ammeter around the supply wire. Operate as normal starting and make note of the current draw indication. The current draw is 16 to 18 amperes at 12 volts. If a cold engine fails to start after the heater coil has operated for 20 seconds and the unit and the area of inlet manifold around the unit are warm, either the starting procedure has not been done correctly or the fault is not the cold start unit.Finding Top Center Compression Position For No. 1 Piston
Locating Top Center Compression Position
(1) Pointer indicator. (2) Dial indicator.1. Fasten a pointer indicator (1) to the front of the timing cover.2. Rotate the crankshaft, in the direction of engine rotation, until the pushrod for the inlet valve of the No.4 cylinder begins to tighten. Use care when rotating the crankshaft. The No.1 inlet valve will be held in position on top of the piston. If the crankshaft is not positioned properly, the valve may fall from the cylinder head.3. Remove the front rocker arm and the No.1 inlet valve spring.4. Fasten a dial indicator (2) with its plunger in contact with the top of the valve stem. Slowly, rotate the crankshaft, clockwise from the front, until the clockwise movement of the dial indicator stops. Make a temporary mark on the front pulley or damper to align with the pointer indicator (1). Continue to rotate the crankshaft, in the same direction until the dial indicator begins to move in a counterclockwise direction. Make another temporary mark on the damper or pulley to align with the indicator. Mark the center point between the two temporary marks. Remove the two temporary marks.5. Rotate the crankshaft approximately 45 degrees counterclockwise from the front and then clockwise until the mark on the pulley or damper is aligned with the pointer indicator. The No.1 piston is now at Top Center on the compression stroke.Check Valve Timing
1. Set the No.1 piston on the TC compression stroke. See, Finding Top Center Compression Position For No.1 Piston.2. Rotate the crankshaft, clockwise from the front, until the inlet valve of the No.4 cylinder is fully open.3. Set the valve lash of the No.1 inlet valve to 1.50 mm (.059 in).4. Rotate the crankshaft, clockwise from the front, until the push rod of the No.1 cylinder inlet valve begins to tighten. In this position, check if the mark on the crankshaft pulley or damper is within 2.5 degrees of the pointer indicator. Use the formula as follows to find the measurement which is equal to 2.5 degrees on the pulley or damper. C=Circumference of pulley or damperP=2.5 degrees5. If the timing is more than 2.5 degrees out of position, the timing gears are not in correct alignment. One tooth on the camshaft gear is equivalent to 23.0 mm (.91 in) at the circumference of a pulley of 203.0 mm (7.99 in) diameter. If a large damper is installed, one tooth on the camshaft gear is equivalent to 35.0 mm (1.38 in) at the circumference of a damper of 310.0 mm (12.20 in) diameter, or 37.0 mm (1.46 in) at the circumference of a damper of 327.0 mm (12.87 in) diameter.6. Rotate the crankshaft, clockwise from the front, until the inlet valve of the No. 4 cylinder is fully open. Adjust the valve lash of the No. 1 cylinder inlet valve to 0.20 mm (.008 in).Fuel Lift Pump Pressure Test
Fuel Lift Pump Pressure Test
(1) Fuel lift pump.1. To test output pressure of fuel lift pump (1), put a pressure gauge in the outlet of fuel lift pump (1). Disconnect the fuel injection pump solenoid wire (if equipped) and put the fuel shutoff lever in the no-fuel position.2. Crank the engine for ten seconds and note the highest indication on the gauge. It should be as follows: Normal Pressure ... 40 to 70 kPa (6 to 10 psi)Minimum Pressure ... 30 kPa (4.5 psi)3. If the pressure is below