Piper Arrow IV, Maintenance Manual

Page: 633 / 752

Figure 74-22. Removing Frozen Spark Plug
4. Removal of seized spark plugs in the cylinder may be accomplished by application of liquid carbon
dioxide by a conical metal funnel adapter with a hole at the apex just large enough to accommodate the funnel
of a CO2 bottle. (Refer to Figure 74-22.) When a seized spark plug cannot be removed by normal means, the
funnel adapter is placed over and around the spark plug. Place the funnel of the CO2 bottle inside the funnel
adapter and release the carbon dioxide to chill and contract the spark plug. Break the spark plug loose with a
wrench. A warm cylinder head at the time the carbon dioxide is applied will aid in the removal of an
excessively seized plug.
5. Do not allow foreign objects to enter the spark plug hole.
INSPECTION AND CLEANING OF SPARK PLUG.
1. Visually inspect each spark plug for the following non-repairable defects:
A. Severely damaged shell or shield threads nicked up, stripped or cross-threaded.
B. Badly battered or rounded shell hexagons.
C. Out-of-round or damaged shielding barrel.
D. Chipped, cracked or broken ceramic insulator portions.
E. Badly eroded electrodes worn to approximately 50% of original size.
2. Clean the spark plug as required, removing carbon and foreign deposits.
3. Set the electrode at .015 to .018 inches.
4. Test the spark plug both electrically and for resistance.
Effectivity 74-22-02
PA-28RT-201T Page 74-20
Revised: July 13, 1983
3E5
PIPER AIRCRAFT
PA-28RT-201 / 201T
MAINTENANCE MANUAL