For "NO SPARK" and "WEAK SPARK" cases.
Fuel system-25%
For "GOOD SPARK" case only.
When test indicates a good spark is occurring at each spark plug,the ignition system may be eliminated and the fuel system should be checked.
Engine misfires-continuous misfiring in one or more cylinders.
*Faulty spark plugs are a frequent cause of engine misfiring-check the following:
1.Is recommended type plug being used?
2.Clean and readjust spark plugs.
3.Inspect porcelain at lower end
A.If porcelain is very WHITE-plug is too HOT-Use COLDER plug.
B.If porcelain is LIGHT BROWN-plug is CORRECT-Replace with same type.
C.If porcelain is BLACK or OILY-plug is too COLD-Use HOTTER plug.
*If the possibility of faulty plugs has been eliminated proceed to check the following:
1.High tension wires may be leaking.
2.Distributor cap may be defective.
3.Cylinder may have insufficient or uneven compression.