0435445 JOHNSON HOOK AY.

Troubleshooting
Troubleshooting can be difficult. The TROUBLESHOOTING INDEX gives a list of possible problems. To make a repair to a problem, make reference to the cause and correction on the pages that follow.This list of problems, causes and corrections will only give an indication of where a possible problem can be, and what repairs are needed. Normally, more or other repair work is needed beyond the recommendations in the list.Remember that a problem is not normally caused only by one part, but by the relation of one part with other parts. This list is only a guide and can not give all possible problems and corrections. The serviceman must find the problem and its source, then make the necessary repairs.1. Engine Will Not Turn When Start Switch is On.2. Engine Will Not Start.3. Misfiring or Running Rough.4. Stall at Low rpm.5. Sudden Changes In Engine rpm.6. Not Enough Power.7. Too Much Vibration.8. Loud Combustion Noise.9. Loud Noise (Clicking) From Valve Compartment.10. Oil In Cooling System.11. Mechanical Noise (Knock) In Engine.12. Fuel Consumption Too High.13. Loud Noise From Valves or Valve Operating Components.14. Little Movement of Rocker Arm and Too Much Valve Clearance.15. Valve Rotocoil or Spring Lock is Free.16. Oil at the Exhaust.17. Little or No Valve Clearance.18. Engine Has Early Wear.19. Coolant In Lubrication Oil.20. Too Much Black or Gray Smoke.21. Too Much White or Blue Smoke.22. Engine Has Low Oil Pressure.23. Engine Uses Too Much Lubrication Oil.24. Engine Coolant Is Too Hot.25. Starter Motor Does Not Turn.26. Alternator Gives No Charge.27. Alternator Charge Rate Is Low or Not Regular.28. Alternator Charge Too High.29. Alternator Has Noise.30. Exhaust Temperature Too High.Engine Crankshaft Will Not Turn When Start Switch Is On Engine Will Not Start Misfiring Or Running Rough Stall At Low RPM Sudden Changes In Engine Speed Not Enough Power Too Much Vibration Loud Combustion Noise (Knock) Loud Noise (Clicking) From Valve Compartment Oil In Cooling System Mechanical Noise (Knock) In Engine Fuel Consumption Too High Loud Noise From Valves Or Valve Drive Components Little Movement Of Rocker Arm And Too Much Valve Clearance Valve Rotocoil Or Spring Lock Is Free Oil At The Exhaust Little Or No Valve Clearance Engine Has Early Wear Coolant In Lubrication Oil Too Much Black Or Gray Smoke Too Much White Or Blue Smoke Engine Has Low Oil Pressure Engine Uses Too Much Lubrication Oil Engine Coolant Is Too Hot Starter Motor Does Not Turn Alternator Gives No Charge Alternator Charge Rate Is Low Or Not Regular Alternator Charge Too High (As Shown By Lights Burning Out, Battery Needs Too Much Water) Alternator Has Noise Exhaust Temperature Is Too High Fuel System
Either too much fuel or not enough fuel for combustion can be the cause of a problem in the fuel system.Many times work is done on the fuel system when the problem is really with some other part of the engine. The source of the problem is difficult to find, especially when smoke comes from the exhaust. Smoke that comes from the exhaust can be caused by a bad fuel injection valve, but it can also be caused by one or more of the reasons that follow: a. Not enough air for good combustion.b. An overload at high altitude.c. Oil leakage into combustion chamber.d. Not enough compression.Fuel System Inspection
A problem with the components that send fuel to the engine can cause low fuel pressure. This can decrease engine performance.1. Check the fuel level in the fuel tank. Look at the cap for the fuel tank to make sure the vent is not filled with dirt.2. Check the fuel lines for fuel leakage. Be sure the fuel supply line does not have a restriction or a bad bend.3. Install a new fuel filter. Clean the primary fuel filter, if so equipped.4. Remove any air that may be in the fuel system. If there is air in the fuel system, use the procedure that follows to remove the air from the fuel system.To prime the pump housing or to fill a new filter with fuel, move the handle of the priming pump up and down several times. DO NOT loosen any fuel lines. The air in the filter goes through the fuel injection pump housing, the constant fuel return valve, and the return line back to the fuel tank. When the filter is full, you will feel an increase of pressure on the priming pump handle. After use of the priming pump, lock the plunger in place by tightening it into the base.If the engine will not start after the air is removed from the filter and housing, it is necessary to bleed the fuel injection lines.Follow this procedure to bleed the fuel injection lines: a. Move the governor control lever to the LOW-IDLE position.b. Loosen all of the fuel injection lines at the cylinder head.c. Turn the engine with the starter motor until fuel flows, free of air bubbles, from all of the fuel lines.d. Move the governor control lever to the SHUTOFF position.e. Tighten the fuel line nuts to a torque of 40 7 N m (30 5 lb. ft.). The hand priming pump CANNOT make enough pressure to open the valves in the injection pumps. To bleed the fuel injection lines, the engine must be turned with the starer motor.5. Inspect the fuel bypass valve to see that there is no restriction to good operation.Checking Engine Cylinders Separately
An easy check can be made to find the cylinder that runs rough (misfires) and causes black smoke to come out of the exhaust pipe.Run the engine at the speed that is the roughest. Loosen the fuel line nut at a fuel injection pump. This will stop the flow of fuel to that cylinder. Do this for each cylinder until a loosened fuel line is found that makes no difference in engine performance. Be sure to tighten each fuel line nut after the test before the next fuel line nut is loosened. Check each cylinder by this method. When a cylinder