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	VISUAL		ANALYSIS
	Copper deposits on center electrode, possibly bridging spark gap to ground electrode(s).		COPPER RUN-OUT. If spark plugs with copper in the center electrode operate at excessively high temperatures, copper run-out generally occurs when the center electrode temperature has exceeded 1900°F, a temperature much higher than the design-intended operating temperature of the electrode. This run-out of copper almost always shorts out the spark plug by bridging the spark gap. Check all engine functions that can prevent spark plugs from operating within their design-intended temperature range. Check to determine if too hot a heat range spark plug has been used in a high output engine. Or perhaps too much or too little installation torque has caused this problem. If so, make sure that spark plugs are being installed with an indicating torque wrench to the spark plug manufacturer's recommendations . Pre-ignition may also be indicated when copper run-out is observed with ignition too far advanced or mixture too lean.To extend the spark plug's temperature range, consider the substitution of spark plugs with electrodes of solid nickel, which will extend temperature limit of center electrode to 2800°F before melting occurs.

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