Aviation Engines Part 25

Broken Spark Plug Insulation.

Carbon Deposits or Oil Between Plug Points.

Spark-Plug Points Too Near Together or Far Apart.

Wrong Cables to Plugs.

Short Circuited Secondary Cable.

Broken Secondary Cable.

Dry Battery Weak. } Storage Battery Discharged. } Battery Systems Poor Contact at Timer. } Only.

Timer Points Dirty. } Poor Contact at Switch. } Primary Wires Broken, or Short Circuited. } Battery and Battery Grounded in Metal Container. } Coil Ignition Battery Connectors Broken or Loose. } System Only.

Timer Points Out of Adjustment. } Defects in Induction Coil. } Ignition Timing Wrong, Spark Too Late or Too Early.

Defective Platinum Points in Breaker Box (Magneto).

Points Not Separating.

Broken Contact Maker Spring.

No Contact at Secondary Collector Brush.

Platinum Contact Points Burnt or Pitted.

Contact Breaker Bell Crank Stuck.

Fiber Bus.h.i.+ng in Bell Crank Swollen.

Short Circuiting Spring Always in Contact.

Dirt or Water in Magneto Casing.

Oil in Contact Breaker.

Oil Soaked Brush and Collector Ring.

Distributor Filled with Carbon Particles.

_Motor Stops Without Warning_

Broken Magneto Carbon Brush.

Broken Lead Wire.

Broken Ground Wire.

Battery Ignition Systems.

Water on High Tension Magneto Terminal.

Main Secondary Cable Burnt Through by Hot Exhaust Pipe (Transformer Coil, Magneto Systems).

Particle of Carbon Between Spark Plug Points.

Magneto Short Circuited by Ground Wire.

Magneto Out of Time, Due to Slipping Drive.

Water or Oil in Safety Spark Gap (Multi-cylinder Magneto).

Magneto Contact Breaker or Timer Stuck in r.e.t.a.r.d Position.

Worn Fiber Block in Magneto Contact Breaker.

Binding Fiber Bus.h.i.+ng in Contact Breaker Bell Crank.

Spark Advance Rod or Wire Broken.

Contact Breaker Parts Stuck.

_Motor Runs Irregularly or Misfires_

Loose Wiring or Terminals.

Broken Spark-Plug Insulator.

Spark-Plug Points Sooted or Oily.

Wrong Spark Gap at Plug Points.

Leaking Secondary Cable.

Prematurely Grounded Primary Wire.

Batteries Running Down (Battery Ignition only).

Poor Adjustment of Contact Points at Timer.

Wire Broken Inside of Insulation.

Loose Platinum Points in Magneto.

Weak Contact Spring.

Broken Collector Brush.

Dirt in Magneto Distributor Casing or Contact Breaker.

Worn Fiber Block or Cam Plate in Magneto.

Worn Cam or Contact Roll in Timer (Battery System only).

Dirty Oil in Timer.

Sticking Coil Vibrators.

Coil Vibrator Points Pitted.

Oil Soaked Magneto Winding.

Punctured Magneto or Coil Winding.

Distributor Contact Segments Rough.

Sulphated Storage Battery Terminals.

Weak Magnets in Magneto.

Poor Contact at Magneto Contact Breaker Points.

DEFECTS IN ELECTRICAL SYSTEM COMPONENTS

To further simplify the location of electrical system faults it is thought desirable to outline the defects that can be present in the various parts of the individual devices comprising the ignition system.

If an airplane engine is provided with magneto ignition solely, as most engines are at the present time, no attention need be paid to such items as storage or dry batteries, timer or induction coil. There seems to be some development in the direction of battery ignition so it has been considered desirable to include components of these systems as well as the almost universally used magneto group. Spark-plugs, wiring and switches are needed with either system.

SPARK-PLUGS

DEFECT TROUBLE CAUSED REMEDY Insulation cracked. Plug inoperative. New insulation.

Insulation oil soaked. Cylinder misfires. Clean.

Carbon deposits. Short circuited spark. Remove.

Insulator loose. Cylinder misfires. Tighten.

Gasket broken. Gas leaks by. New gasket.

Electrode loose on sh.e.l.l. Cylinder misfires. Tighten.

Wire loose in insulator. Cylinder misfires. Tighten.

Air gap too close. Short circuits spark. Set correctly.

Air gap too wide. Spark will not jump. Set points 1/32"

apart.

Loose terminal. Cylinder may misfire. Tighten.

Plug loose in cylinder. Gas leaks. Tighten.

Mica insulation oil soaked. Short circuits spark. Replace.

MAGNETO

DEFECT TROUBLE CAUSED REMEDY Dirty oil in distributor. Engine misfires. Clean.

Metal dust in distributor. Engine misfires. Clean.

Brushes not making contact. Current cannot pa.s.s. Strengthen spring.

Distributor segments worn. Engine misfires. Secure even bearing.

Collecting brush broken. Engine misfires. New brush.