OCR Text |
Show Cracks Permit Current Leakage in Spark Plug The most common trouble with spark plugs is caused by cracked Insulators, In-sulators, which then allow of current leakage, causing a poor spark or none at all at tlie gap. Often one cannot tell by examining the outside whether the insulator is cracked, because the trouble may be in the hidden portion.' The only safe way is either to dismantle dis-mantle the plug if it is not of the one-piece type, or test it by laying it on tlie cylinder head with the plu cable attached. Then by cranking the engine, the gap may be watched for a good spark.. Cracks, except hidden ones, may at once be noticed if the engine is operating In a dark area; sparks will be seen on the outside o" the insulator. |