Boletines De Magnetos

TELEDYNE CONTINENTAL

®

AIRCRAFT ENGINE

MANDATORY SERVICE BULLETIN
The Subject Matter of this Service Bulletin is Incorporated In
Whole or in Part in an FAA Airworthiness Directive

CATEGORY 1

MSB94-8A
FAA APPROVED
SUPERSEDES M88-8R1
and SB94-8

SUBJECT:

MAGNETO TO ENGINE TIMING

PURPOSE:

A. To provide magneto to engine timing procedure for all TCM engines.
Theimportance of establishing and maintaining correct magneto to engine
timing cannot be over-emphasized. Incorrect timing, in addition to producing
a rough running engine, can lead to detonation, pre-ignition and internal
engine damage or failure.
B. To provide O-200-A and B engine models that are eligible for magneto timing
advance. See timing table Note 5 and Figures 1 and 2.

COMPLIANCE:MODELS
AFFECTED:

At every 100 hour inspection, annual inspection, progressive inspection,
whenever magneto maintenance is performed or whenever magnetos are
removed or replaced. Magneto maintenance and internal magneto timing must
be conducted in accordance with magneto manufacturer's instructions.
All.
WARNING

Magneto-to-engine timing maintenance does not assure magneto, harness andspark plug performance. Failure to properly maintain the magneto, harness
and spark plugs will lead to internal engine damage and failure. Magneto,
ignition harness and spark plugs must be maintained in accordance with the
manufacturer's instructions.
NOTE: A single severe "kick back" while cranking the engine can cause failure of components of
the cranking system. Kick back can be caused byintermittent operation of the impulse
couplings or shower of sparks system. Perform the following operational tests at the
specified intervals to insure that these systems are functioning properly. It is important to
note that these operational tests (paragraph I & II) do not supersede inspection,
maintenance and overhaul instructions set forth in current manufacturer's service bulletins
andoverhaul manuals.
I.

As part of the routine 100 hour, annual or progressive inspection, whichever occurs most
often, for all TCM engines incorporating impulse coupled magnetos, perform the following
"magneto impulse coupling operational test."
WARNING:
Failure to properly ground magnetos will result in engine ignition and possible
injury to personnel.

ISSUED

TELEDYNE CONTINENTAL MOTORSREVISED

MO

DAY

YEAR

09

14

94

MO

DAY

YEAR

10

09

96

P.O. Box 90 MOBILE ALABAMA 36601
334-438-3411

PAGE NO REVISION

1 of 6
MSB94-8A

A

1. Assure that both magnetos are properly grounded. With all spark plugs installed in all
cylinders, remove all spark plug harness lead ends from the spark plugs and ground to
the engine to prevent ignition.2. a. Magneto switch, if separate from starter switch - off.
b. Mixture - idle cut off.
c. Throttle - closed.
d. Fuel selector - off.
e. Master switch - on.
3. Crank engine several revolutions.
WARNING
Use extreme caution in the area of the propeller while performing this test.
a. Impulse coupling operation is audible and can also be felt through the magneto
housings. They should "click"together and consistently while cranking the engine.
b. If "no clicking" or "intermittent clicking" is discovered, remove magneto and service
per manufacturer's instructions.
NOTE: Some engine installations incorporate only one impulse coupling on the left
magneto, with the right magneto grounded through the ignition switch during
starting. Verify the number of impulse couplings that are usedfor the particular
magneto/engine installation. For those that use only one impulse coupling, verify
that the non-impulse coupling magneto is grounded during starting. See paragraph
II, 1.
II.

As part of the routine 100 hour, annual or progressive inspection, whichever occurs most
often, for all TCM engines incorporating a shower-of-sparks ignition system, perform the
following...