Engine does not turn over with starter
- Low battery
- Loose or corroded battery terminals
- Open in wiring to starter or poor engine or battery ground
- Faulty starter or solenoid (see chapter 10)
- Faulty ignition/starter switch
- Major mechanical failure (jammed engine)
- Piston rings rusted to liners (after a long idle time)
Starter turns engine over slowly
- Low battery
- Loose or corroded battery terminals
- Open in wiring to starter or poor ground to engine or battery
- The engine is filled with the wrong brand of oil Starter failure (see chapter 10)
Engine cranks normally with starter, but won't start
- Damp or dirty ignition wires
- Breaker contacts dirty or incorrectly adjusted
- Spark plugs stuck or have incorrect spark gap
- Break in ignition wires
- Other malfunctions of the ignition system (see chapter 4)
- Empty fuel tank or defective fuel pump
- Excessive or insufficient suction
- Air damper actuator incorrectly adjusted
- Clogged air cleaner
- Clogged jet (jets) carburetor
- Other fuel system malfunctions (see chapter 3)
- Valve clearances incorrectly adjusted
- Valve timing incorrectly adjusted (after engine overhaul)
- Bad compression in the cylinders
Engine cranks but won't start
- Loose ignition wire contacts or internal wire break
- Intake manifold or carburetor gasket leaking air
- Faulty fuel pump
- Other fuel system malfunctions (see chapter 3)
Rough idle
- Carburetor misaligned or clogged (see chapter 3)
- Ignition timing incorrectly adjusted (see chapter 4)
- Valve clearances incorrectly adjusted
- Intake manifold or carburetor gasket leaking air
- Clogged air filter
- Different compression in the cylinders due to their wear or gas leakage
- Worn distributor
- Worn parts of the gas distribution mechanism or valve mechanism
Flash Skip
- Spark plugs stuck or have incorrect spark gap
- Wet, dirty or internally damaged high voltage wires
- Breaker contacts thrown or incorrectly adjusted
- Other malfunctions of the ignition system (see chapter 4)
- Intake manifold or carburetor gasket leaking air
- Carburetor misadjusted or clogged jet (jets)
- Dirty fuel
- Other fuel system malfunctions (see chapter 3)
- Valve clearances incorrectly adjusted
- Valve stuck, seated incorrectly, or burnt
- Broken valve spring (valves)
- Different compression in the cylinders due to their wear or gas leakage
The engine does not develop the required power
- Ignition timing incorrectly adjusted
- Clogged air cleaner
- Engine overheating
- Carburetor misadjusted or clogged jet (jets)
- Valve clearances incorrectly adjusted
- The distributor does not work well (automatic ignition controls not working)
- Sticky brakes
- Excessive carbon buildup in the cylinder head
- Bad compression
- Valve timing incorrectly adjusted (after engine overhaul)
Detonation or knocking when increasing engine speed
- Incorrect fuel octane rating
- Ignition too early or automatic ignition controls not working
- Carburetor misadjusted
- Overheat
- Excessive carbon buildup in the cylinder head
- Valve timing incorrectly adjusted (after engine overhaul)
The engine makes an unusual noise
- Unintended metal contact (e.g. fan blades)
- Worn drive belt
- Peripheral hardware failure (e.g. water pump or generator)
- Too large valve clearances (knocking sound)
- Worn sprockets or timing chain
- Broken piston ring (rings) (ticking sound)
- Worn connecting rod bearings (knock, may decrease under load)
- Worn main bearings (heavy thuds, may increase under load)