Craftsman 143.991200 Specifications download pdf (Page 57)

The flywheel with magnets provide the magnetic flux

(or field) which is necessary to induce voltage and

trigger the module to provide spark.

The flywheel key locates the flywheel to the

crankshaft in the proper position for ignition timing. If

a flywheel key is sheared, or partially sheared, the

engine will not start or can be difficult to start (diag.

3).

NOTE: Always replace flywheel keys by Model and

Specification Number. Tecumseh has some keys that

look similar but affect ignition timing.

MAGNETS

3/4" (19.05 mm)

TESTING PROCEDURE

1. Check for spark using a commercially available

spark tester and following the tester's

recommended procedure.

2. Check the spark plug for cracks in the porcelain,

pitted or burned electrodes, excessive carbon

buildup, and proper .030" (.762 mm) air gap

setting. Replace if questionable. Try to start and

run the engine. If the engine will not start or run

properly proceed to step #3.

3. Attach the spark plug wire to the spark plug

tester and ground the tester as in step #1.

Remove the blower housing, disconnect the

ignition grounding lead at the ignition module.

Reinstall the blower housing and crank the

engine over. If spark occurs, check the ignition

switch, safety interlock switches, or electrical

wiring for shorting to ground.

4. Check the air gap between the flywheel magnets and the laminations of the ignition module. It should be

.0125" (.3175 mm) or use gauge part # 670297.

5. Check the flywheel magnets for the proper strength using this rough test. Hold a screwdriver at the

extreme end of the handle with the blade down, move the blade to within 3/4 inch (19.05 mm) of the

magnets. If the screwdriver blade is attracted to the magnets, the magnetic strength is satisfactory (diag.

4).

6. Examine the ignition module and lamination assembly for cracks in insulation or other damage, which

would cause shorts or leakage of current.

7. Check the operation of the ignition module using an approved tester following the instructions furnished

with the test unit, or booklets offered by the Tecumseh Products Co. Engine and Transmission Group

Service Division.

Ignition modules are permanently attached to the lamination and must be serviced as an assembly.

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Craftsman 143.991200 Specifications Page 57

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