Advanced Small Engine Maintenance and Repair Projects

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Chapter 8

• Advanced Small Engine Maintenance and Repair
  Projects

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• A friction surface is placed in contact with a
  drive disc, which is connected to an engine.

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• Certain engine components must first be removed
  before an engine can be cleaned of carbon
  deposits.

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• For best operation, the cylinder should be
  removed and cleaned of carbon deposits every 100
  hours of operation.

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• A cylinder head is easily reassembled once carbon
  deposits have been removed.

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• A reference chart can be consulted to review and
  illustrate the proper method for using a DMM on a
  Briggs Stratton engine electrical system or
  component.

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• An AC voltage test is first performed to verify
  that a stator has the potential to provide
  current to a regulator.

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• DC current exiting a regulator/rectifier is
  tested to verify that the electrical system of an
  engine is operating properly.

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• A stator located under a flywheel is accessed by
  removing the flywheel, screen, and blower housing.

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• When a stator is mounted outside a flywheel, the
  stator is easily removed by loosening the two
  mounting bolts and lifting it off the engine.

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• The air gap between a stator and flywheel must be
  set precisely for the stator to function properly.

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• Ignition armatures have evolved from being of the
  breaker-points to solid-state types.

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• An ignition armature is installed by using a
  socket wrench and feeler gauges.

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• A stop switch is tested by attempting to start
  the engine while it is connected to a spark
  tester.

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• To improve engine operation and extend the
  operating life of the engine, an old ignition
  module can be removed and replaced with a more
  modern ignition module.

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• The valve design for a four-stroke cylinder small
  engine includes one intake valve and one exhaust
  valve per cylinder.

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• The valves of L-head engines are located on one
  side of the cylinder. The valves of overhead
  valve engines are located in the cylinder head.

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• A tappet clearance is the spacing between the
  valve stem and the tappet. It may need to be
  adjusted after lapping and re-installing a valve.

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• The valve chamber on a small engine is accessed
  by removing the muffler, crankcase breather, and
  cylinder head.

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• Spring retainers are removed with a valve spring
  compressor and needle-nose pliers.

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• Valves are removed after compressing the springs
  and removing the retainers, compressors, and
  springs.

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• Valves are inspected to help identify the source
  of an engine problem.

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• Valve lapping is done to repair minor scoring and
  pitting of the valve face and seat and to restore
  the ability of the valve to seal the combustion
  chamber.

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• Valves with spring retainers are reinstalled
  using valve spring compressors.

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• The parts of an over-head valve cylinder head
  may differ, depending on the engine model and
  manufacturer.

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• Overhead valves are reinstalled using a torque
  wrench and socket wrench or nut driver set.

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• Overhead valves must be adjusted for proper
  operation once they are reinstalled.