ST WBE120, Operator'S Manual

Page: 85 / 281

9
5.7 SPARK PLUG CHECKS
AND MAINTENANCE
1. Take the spark plug down (fig. 10.A)
using a socket wrench (fig. 10.B).
2. Clean the electrodes (fig. 10.C) with a metal
brush, removing any carbonaceous build-up.
3. Using a thickness gauge (fig. 10.D)
ensure the gap between electrodes
is correct (0.6 - 0.8 mm).
4. Put the spark plug back in
(fig. 10.A) and tighten firmly using
a socket wrench (fig. 10.B).
Replace the spark plug if the electrodes are
burnt or if the porcelain is broken or damaged.
Fire hazard! Do not check the ignition
system when the spark plug is not in place.
IMPORTANT Only use the required type
of spark plugs (see Technical data table).
6. TROUBLESHOOTING
PROBLEM PROBABLE CAUSE SOLUTION
1. Difficulty staring
the engine
No fuel Check and top up (chap. 5.1.3)
Old fuel or deposits in the fuel tank Empty the fuel tank and add fresh fuel
Incorrect starting procedure
Perform start-up correctly
(par. 5.2 and par. 5.3)
Disconnected spark plug
Ensure that the cap is fitted onto
the spark plug (par. 5.1.4)
The spark plug is wet or the
spark plug electrodes are dirty
or placed inadequately
Check (par. 6.6)
Clogged air filter Check and clean (par. 6.5)
Incorrect oil for the season Replace with suitable oil (par. 6.3)
Fuel evaporation in the
carburettor (vapour lock)
due to elevated temperatures
Wait a few minutes then try
starting it up again (par. 5.3)
Carburetion fault Contact an Authorised Assistance Centre
Low battery Recharge the battery (par 5.3.1)
Battery is not inserted correctly Insert the battery correctly (par. 5.3.3)
2. Irregular operation.
Dirty spark plug electrodes
or incorrect gap
Check (par. 6.6)
The spark plug cap inserted incorrectly Ensure that the cap is firmly
fitted on (par. 5.1.4)
Clogged air filter Check and clean (par. 6.5)
Carburetion fault Contact an Authorised Assistance Centre
3. Loss of power
during operation
Clogged air filter Check and clean (par. 6.5)
Carburetion fault Contact an Authorised Assistance Centre
If problems persist after implementing the solution, contact your Dealer.