Motor Stops In Flight
Gasoline Shut-Off Valve Jarred Closed.
Gasoline Supply Pipe Clogged.
No Gasoline in Tank.
Spray Nozzle Stopped Up.
Water in Spray Nozzle.
Particles of Carbon Between Spark-Plug Points.
Magneto Short Circuited by Ground in Wire.
Air Lock in Gasoline Pipe.
Broken Air Line or Leaky Tank (Pressure Feed System Only).
Fuel Supply Pipe Partially Clogged.
Air Vent in Tank Filler Cap Stopped Up (Gravity and Vacuum Feed System).
Float Needle Valve Stuck.
Water or Dirt in Spray Nozzle.
Mixture Adjusting Needle Jarred Loose (Rotary Motors Only).
Motor Races, Will Not Throttle Down
Air Leak in Inlet Piping.
Air Leak Through Inlet Valve Guides.
Control Rods Broken.
Defective Induction Pipe Joints.
Leaky Carburetor Flange Packing.
Throttle Not Closing.
Poor Slow Speed Adjustment (Zenith Carburetor).
Motor Misfires
Carburetor Float Chamber Getting Dry.
Water or Dirt in Gasoline.
Poor Gasoline Adjustment (Rotary Motors).
Not Enough Gasoline in Float Chamber.
Too Much Gasoline, Carburetor Flooding.
Incorrect Jet or Choke (Zenith Carburetor).
Broken Cylinder Head Packing Between Cylinders.
Noisy Operation
Popping or Blowing Back in Carburetor.
Incorrectly Timed Inlet Valves.
Inlet Valve Not Seating.
Defective Inlet Valve Spring.
Dirt Under Inlet Valve Seat.
Not Enough Gasoline (Open Needle Valve).
Muffler or Manifold Explosions.
Mixture Not Exploding Regularly.
Exhaust Valve Sticking.
Dirt Under Exhaust Valve Seat.