Checks and inspections

1. Slacken the four fastening screws and remove the ignition coils from the support bracket.

CHECKS AND INSPECTIONS

• Check that the characteristics of the ignition coils are within the specified limits. If not change the coils.

SPARK PLUGS

The standard spark plugs fitted may be of the type with surface discharge with four peripheral points and a centre electrode for 8V engines and one point and central electrode for 16V engines.

The former does not need adjustment of the gap between the electrodes, while the latter has a precise dimension to be respected as illustrated.

Firing order 1 - 3 - 2 - 4

CHECKING AND REPLACEMENT

• With the engine cold disconnect the spark plug cables
• Blow in the cavities to remove any impurities and traces of dirt.
• Slacken and remove the spark plugs.

For the BOXER 16V engine use tools no. N° 1.822.103.000 and no.1.822.107.000.

• Check the state of cleaning, or for any breaks of the ceramic insulation. In which case replace the spark plugs.

The use of spark plugs with specifications and size other than those specified may cause serious damage to the engine and alter the level of harmful emission at the exhaust.

A dirty or burnt spark plug is often a symptom of malfunctioning of the engine supply system. For example:

• traces of carbon dust: incorrect mixture, air cleaner very dirty;
• oil stains: oil leaks from the piston rings;
• formation of ash: presence of aluminium materials, to be found particularly in the oil;
• melted electrodes: overheating due to unsuitable fuel, faults in the valves;
• high electrode wear: harmful additives in the fuel or in the oil, pinging in the head, overheating;
• etc.

• When refitting tighten the spark plugs to a torque of:

25 ÷ 30 Nm
2.5 ÷ 3.1 kgm