2. Insert the rotating cleaning tool (CL-241) into the plug barrel until end bottoms against contact cap. Work plug
back and forth (3/8" stroke) five or six times.
3. Examine ceramic sleeve internal surfaces. If satisfactorily clean, rinse out with a fountain type jet of warm water
(120o to 150o F). If the ceramic sleeve is chipped or cracked, scrap the spark plug.
4. Air-blast sleeve end of each plug and place into a holding tray, shield end down. Generally, the heat from the hot
water is sufficient for thorough drying out, but for positive drying, the plugs should be placed into a 225o F oven
for 30 minutes.
Replaceable rubber cleaning tools, Type CL-241, are available as service
parts for the AV17-1 assembly.
VI. Gap Setting
The resetting of spark plug electrode gaps must always be accomplished by the adjustment of the side or ground
electrodes only. Never attempt to bend or move the center electrode because ceramic tip fracture will result.
FINE WIRE AIRCRAFT SPARK PLUG GAP SETTING TOOL TYPE AV20-3
OPERATING INSTRUCTIONS
1. Fasten gap setting tool onto a conveniently located work bench or table top so the handle position is freely
accessible.
2. Insert firing end of spark plug into the tool adapter bushing, so that protruding tool jaws will enter the firing end
cavity.
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