PRODUCT INFORMATION
INDEX
DATE
Dep.2
IO-G-M-33-001e C
June 2013
CONVENTIONAL SPARK PLUG CHANGING AND
MAINTENANCE INSTRUCTIONS
3/3
5. VISUAL INSPECTION OF THE SPARK PLUG CONDITION
ID
CONDITION
POSSIBLE CAUSE
1
Small deposits of white ashes on the electrodes
NORMAL
2
Electrodes or casing fused
PREMATURE DETONATION OR IGNITION
(Possible faulty carburetion, ignition timing or poor quality of
the gas used)
3
Orange-colour residues on spark plug end
ANTIFREEZE RESIDUES
(Possible entry of cooling water into the chamber)
4
Granular red deposits on insulator or spark plug end
IRON OXIDE DEPOSITS
5
White-yellowish deposits on the electrodes
SILICON DIOXIDE DEPOSITS
(Possible content of silicon in the fuel gas or intake air)
6
Rough white deposits on spark plug end
DEPOSITS OF CALCIUM OR BARIUM
(These elements normally proceed from oil, but calcium also
exists in water)
7
Hard whitish deposits on the spark plug
DEPOSITS OF BURNT OIL
(Possible wear or scratching of cyl. liner and/or piston rings.
Generally associated with high blow-by)
8
Black specks on the spark plug end
CINDER DEPOSITS
(Probably due to incomplete combustion or problems with oil
in the chamber)
In many occasions, the forming of those deposits on the spark plugs is associated with the contamination of a
given motor oil component. It is therefore recommended that oil analysis should be made in order to determine
the oil components out of tolerance.
ID
Representative oil component
ID
Representative oil component
1 Normal
oil
5 Silicon
2 Aluminium
6 Water
3 Water,
glycol
7 Total solids, iron
4 Iron
8 Total solids, iron
When detecting any of the above mentioned conditions, eliminate the root cause before installing a new spark
plug.
5.2.25
O&M_2.002211.810_A_10_2016
