Testing; Service; Air Gap Setting; Spark Plug Service - Tecumseh TC Series Technician's Handbook

TESTING

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 build-up and
proper air gap setting. Replace if questionable.
3. Check the air gap between the ignition module and the flywheel magnet. See "Service" in this chapter.
4. Disconnect the ignition grounding lead at the ignition coil and crank the engine over. If spark occurs, check the
ignition switch or the electrical wiring for shorting to ground. If no spark, test the ignition module using a coil tester
or replace the ignition module.

SERVICE

AIR GAP SETTING

Timing on the solid state module is fixed. The air gap dimension
between the laminations of the ignition module and the magnet
is .0125" (.317 mm) (use gauge part # 670297) for TC 300
rotary mower engines and all TC 200 engines. All other
TC 300 applications require a .030" (.762 mm) air gap
dimension (use gauge part # 670321). Loosen the module
mounting bolts, insert the air gap gauge, hold the module
against the flywheel magnets and torque the mounting screws
to the specification. Remove the gauge and rotate the flywheel
to check for any possible striking points. If none are found, the
air gap is set correctly (diag. 6-3).
NOTE: When using the 670321 gauge push the module tight
to the flywheel before tightening.

SPARK PLUG SERVICE

Spark plugs should be removed, cleaned, and adjusted
periodically. If the porcelain shows cracking, or the electrodes
show evidence of pitting, burning, or excessive carbon build-
up, replace the spark plug.
NOTE: DO NOT USE A SAND BLASTER TO CLEAN SPARK
PLUGS. MICROSCOPIC PARTICLES LEFT IN THE PLUG
CAN SCORE THE ENGINE CYLINDER DURING
OPERATION. Use solvent and a wire brush to clean the plug
and compressed air to blow out completely.
Consult the Master Parts Manual for the correct spark plug
and replace if necessary. Set the spark plug gap at .030" (.762
mm) (diag. 6-4). Install the spark plug in the engine and tighten
to 230 inch pounds (2.6 Nm) torque. If a torque wrench is not
available, screw the spark plug in as far as possible by hand
and use a spark plug wrench to turn the spark plug 1/8 to 1/4
of a turn more if using the old plug, and a 1/2 of a turn more if
using a new spark plug.
www.SmallEngineDiscount.com
All TC300 non-rotary
mower use .030" (.762 mm)
Air gap part number 670321
Not For Resale
.0125" (.7317 mm)
part number 670297
All TC200 an TC300 rotary
mower application
.030"
(.762 mm)
6-3
6-4
23