Trouble Chart Engine

Note: Too frequently, spark plugs and or ignition coil are thought to be defective when engine starts hard, runs irregularly, or fails to start.

Sometimes when a spark plug fails to function normally, it is the result of an accumulation of dirt on plug core which becomes a conductor when damp or wet, allowing spark to jump from cable terminal to plug base, instead of across electrodes in combustion chamber. Under such a condition, wiping plug core clean with a dry rag will allow plug to function normally.

An ignition coil suspected of being defective may only need new spark plug cables installed. Cable insulation eventually deteriorates and sometimes cracks at the point where cable enters coil case. Spark may then jump from cable to cable packing nut (on coil case) instead of across electrodes in combustion chamber, especially if cables are damp or wet.

If engine starts hard:

1. Spark plugs in bad condition, or partially fouled.

2. Spark plug cables in bad condition and "leaking."

3. Circuit breaker points out of adjustment or in need of cleaning.

4. Battery nearly discharged.

5. Loose wire connection at one of battery terminals or at coil or circuit breaker.

6. Carburetor not adjusted correctly.

7. Defective ignition coil.

8. Defective condenser.

If engine starts but runs irregularly or misses :

1. Spark plugs in bad condition, or partially fouled.

2. Spark plug cables in bad condition and "leaking."

3. Spark plug gap too close.

4. Circuit breaker points out of adjustment or in need of cleaning.

5. Condenser connections loose.

6. Defective ignition coil.

7. Defective condenser.

8. Battery nearly discharged.

9. Loose wire connection at one of battery terminals or at coil or circuit breaker.

10. Intermittent short circuit due to damaged wiring insulation.

11. Water or dirt in fuel system and carburetor.

12. Gasoline tank cap vent plugged and tank air bound.

13. Carburetor not adjusted correctly.

14. Weak or broken valve springs.

If engine fails to start, it may be due to one or more of the following conditions:

1. Gasoline tank empty.

2. Gasoline valve shut off.

3. Gasoline line clogged.

4. Discharged battery or loose or broken battery terminal connection. Check by turning light switch "ON."

5. Fouled spark plugs.

6. Spark plug cables in bad condition and "leaking."

7. Badly oxidized ignition circuit breaker points.

8. Circuit breaker points badly out of adjustment.

9. Loose wire connection at one of battery terminals or at coil or circuit breaker.

10. Defective ignition coil.

11. Defective condenser.

12. Clutch slipping and starter not turning engine over.

13. Sticking valves, or tappets too tight.

14. Engine flooded with gasoline as a result of over-choking.

If a spark plug fouls repeatedly.

1. Too cold a plug for the kind of service or for type of engine.

2. Piston rings badly worn or in bad condition otherwise.

3. Oil pump improperly adjusted—oil pressure too high.

4. O.H.V. Engine—intake valve spring cover oil return line clogged with carbon or sludge. One or more push rod cover cork washers in bad condition or push rod covers not seating properly against cork washers.

If engine preignites:

1. Excessive carbon deposit on piston head or in combustion chamber.

2. Too hot a spark plug for the kind of service or for type of engine.

3. Defective spark plugs.

If engine overheats:

1. Insufficient oil supply, or oil not circulating.

2. Leaking valves.

3. Heavy carbon deposit.

4. Carburetor high speed adjustment too lean.

5. Ignition timing too late.

If engine detonates:

1. Unsuitable fuel (octane rating too low).

2. Heavy deposit of carbon on piston head and in combustion chamber (decreases combustion space, thereby increasing compression ratio. The higher the compression ratio, the higher the octane rating of fuel required).

If oil does not return to oil tank:

1. Oil tank empty.

2. Scavenger pump gear key sheared.

3. Oil feed pump not functioning.

If engine uses too much oil:

1. Breather valve incorrectly timed.

2. Oil pressure too high—readjust oil pump.

3. Piston rings badly worn or in bad condition otherwise.

4. O.H.V. Engine—intake valve spring cover oil return line clogged with carbon or sludge. One or more push rod cover cork washers in bad condition or a push rod cover not seating properly against its washer.

5. Chain oiler adjusting screw adjusted for an excessive amount of oil.

Excessive vibration:

1. Cylinder bracket loose or broken.

2. Engine mounting bolts loose.

3. Broken frame.

4. Front chain badly worn, or links tight as a result of insufficient lubrication.

5. Transmission and/or transmission sub-mounting plate loose in chassis.

Generator

If generator does not charge:

1. Brushes badly worn.

2. Brushes sticking in holders.

3. Relay, or current and voltage regulator, not grounded.

4. Defective relay or current and voltage regulator.

5. Commutator dirty or oily.

6. Positive brush holder grounded.

7. Generator "relay" terminal grounded.

8. Loose or broken wire in generator-battery circuit.

9. Broken field coil wire or loose terminal (both coils).

10. Commutator shorted.

11. Defective armature.

If generator charging rate is below normal:

1. Regulating brush not properly adjusted.

2. Current and voltage regulator not properly adjusted.

3. Broken field coil wire or loose terminal (one coil).

4. Commutator worn and not turning true with shaft —throws brushes at high speed.

5. Commutator dirty or oily.

6. Brushes gummy and sluggish in holders.

7. Defective armature.

Carburetor

If carburetor floods:

1. Float set too high.

2. Float valve sticking.

3. Float valve and/or valve seat worn or damaged.

4. Dirt or other foreign matter between float valve and its seat.

5. Carburetor float not located correctly in bowl— may be binding.

Transmission

If transmission shifts hard:

1. Bent shifter rod.

2. Clutch dragging slightly.

3. Transmission oil too heavy (winter operation).

4. Shifter forks (inside transmission) sprung as a result of using too much force when shifting.

5. Corners worn off shifter clutch dogs (inside trans mission)—makes engagement difficult.

If transmission jumps out of gear:

1. Shifter rod improperly adjusted.

2. Shifter forks (inside transmission) improperly adjusted.

3. Shifter engaging parts (inside transmission) badly worn and rounded.

If clutch slips:

1. Clutch controls improperly adjusted.

2. Insufficient clutch spring tension.

3. Worn and/or oil soaked friction discs.

If clutch drags or does not release:

1. Clutch controls improperly adjusted.

2. Clutch spring tension too tight.

3. Friction discs gummy.

4. Clutch key ring badly worn.

If clutch chatters:

1. Clutch disc rivets loose.

2. Clutch sprung disc too flat.

(Continued on next page)

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