0312455 JOHNSON SCREW,Upper mounting

Possible Causes/Corrections Cold Outside Temperatures
It may be necessary to use starting aids, or to heat engine oil or coolant at temperatures below -12°C (10°F). Air In Fuel SystemWith air in the fuel system, the engine will normally be difficult to start, run rough, and release a large amount of white smoke. If the engine will not start, loosen a fuel injection line nut at the through the head adapter and crank the engine until fuel comes out. Tighten the fuel line nut. Start the engine. If the engine still does not run smooth or releases a large amount of white smoke, loosen the fuel line nuts one at a time at the through the head adapters until the fuel that comes out is free of air. Tighten the fuel line nuts. If the air can not be removed in this way, put 35 kPa (5 psi) of air pressure to the fuel tank.
Do not use more than 55 kPa (8 psi) of air pressure in the fuel tank or damage to the tank may result.
Check for leakage at the connections between the fuel tank and the fuel transfer pump. If leaks are found, tighten the connections or replace the lines. It there are no visual leaks, remove the fuel supply line from the tank and connect it to an outside fuel supply. If this corrects the problem, the suction line (standpipe) inside the fuel tank has a leak. Low Quality FuelRemove a small amount of fuel from the tank and check for water in the fuel. If there is water in the fuel, remove fuel from the tank until it is free of water and fill with a good quality fuel. For more information see Special Instruction, Form No. SEHS7067, Fuel Recommendations For Caterpillar Diesel Engines.Change the fuel filter and "prime" (remove the air and/or low quality fuel from the fuel system) the fuel system with the fuel priming pump. If there is no water in the fuel, prime and start the engine by using an outside source of fuel. If engine starts correctly using different fuel, remove all fuel from the tank and fill with good quality fuel. Prime the fuel system if necessary. Low Fuel PressureChange the primary and secondary fuel filters and check to make sure the fuel lines are not plugged or damaged. If the filters or lines are not the cause, a repair or replacement of the fuel transfer pump is needed. Fuel Injection Timing Not CorrectCheck and make necessary adjustments as in Testing and Adjusting Section of this Service Manual. Valve Adjustment Not CorrectCheck and make necessary adjustments as in Testing and Adjusting Section of this Service Manual. Intake valve lash is 0.38 mm (.015 in) and exhaust valve lash is 0.64 mm (.025 in). Defective Fuel Nozzle(s)Remove the fuel nozzles and test as in Testing and Adjusting Section of this Service Manual. Low CompressionSee "Misfiring and Running Rough".Exhaust Smoke Cannot Be Seen While Starting
Possible Causes/Corrections
No Fuel In Tank(s)Check fuel level visually (do not use the fuel gauge only). Be sure tank selection valve is open to the tank with fuel in it. Be sure valve in fuel line between the tanks is open. No Fuel From Fuel Injection PumpLoose a fuel injection line nut at the through the head adapter. With ignition switch in the ON position and accelerator in the FUEL ON position, turn the engine with the starter to be sure there is no fuel from the fuel injection pump. To find the cause for no fuel, follow Steps (a) through (d) until the problem is corrected. a. Use the priming pump to make sure the fuel lines and fuel injection pump housing are full of fuel.b. Check the shut-off solenoid. With the ignition switch on the plunger should be fully retracted to allow full rack travel. Also, remove the rack position indicator cover and check to see if the fuel rack has moved to the "FUEL ON" position (toward rear of engine). This can be an indication of possible governor problems. If rack travel is restricted, replace the solenoid or repair the governor.c. If you are not using a good quality of fuel at temperatures below -12°C (10°F), it is possible that the fuel in the system can "wax" (not have correct flow characteristics) and cause a restriction in the fuel system. Install a new fuel filter. It may be necessary to drain the complete fuel system and replace with a No. 1 grade of fuel.d. Check for fuel supply line restriction by removing the fuel supply line for the fuel filter base. Put 35 kPa (5 psi) of air pressure to the fuel tank.
Do not use more than 55 kPa (8 psi) of air pressure in the fuel tank or damage to the tank may result.
If there is no fuel, or only a weak flow of fuel from the fuel supply line, there is a restriction in the fuel supply line and/or the fuel tank. Exhaust System Not OpenLoosen the exhaust pipe from the exhaust manifold. If engine will now start, check the exhaust system for damage and, or restrictions.