Gap Setting Tool Instructions
1. Fasten gap setting tool in a convenient position on the work bench.
2. Use floating bushing in gapping tool for gapping 14 mm spark plugs. Insert loose bushing into floating bushing
for gapping 18 mm spark plugs.
3. Insert spark plug firing end into tool bushing so protruding jaws enter firing end cavity.
4. Place gap size spacer between center electrode and ground electrode. Push button on top of gap setting tool so
both ground electrodes are squeezing the spacer gauge against the center electrode.
5. Remove gapped spark plug from gap setting tool and install next spark plug. Repeat above operation.
ELECTRICAL TESTING INSTRUCTIONS
HI-TENSION CABLE HAS HIGH VOLTAGE WHEN H. T. BUTTON IS DEPRESSED.
1. Select two spark plug adapters to fit the spark plugs being tested, 14 or 18 mm, and screw into compression
2. Screw spark plug, less gaskets, finger tight into each chamber. For best results, a slight air leak is necessary.
All spark plugs should be cleaned and gapped to manufacturer's specifications.
3. Insert terminal connector into spark plug terminal end (shielded aircraft type).
4. Place H.T. wire clip on terminal connector in spark plug.
5. Push H.T. voltage button and slowly turn pressure valve.
6. Observe spark plug firing in mirror located under spark plugs while air pressure is increased in compression
A. Spark shall be bright and continuous throughout increase of pressure from 115 to 135 psig. (Occasional
sparking may be noted at terminal end under high pressures.)
B. If plug stops firing during increase of pressure from 20 to 90 psig, check terminal and contact ends of plug
for chipped or cracked insulators and overall cleanliness. If insulator is chipped or cracked, reject plug. If
dirty, clean and retest. If plug fails second test, reject it.