Ignition System - Husqvarna HS 139A Workshop Manual

6.7 Ignition system

6.7.1 To remove and install the ignition module
1. Remove the 3 nuts.
2. Remove the engine cover and the flywheel housing.
3. Disconnect the spark plug cap from the spark plug.
4. Remove the 2 bolts and remove the ignition module.
5. Install in the opposite sequence. Make sure that the
air gap is correct. Refer to
wear limits on page 45 .
30 - Repair instructions
Standard dimensions and
6.7.2 To examine the spark plug
CAUTION: Always use the recommended spark
plug type. Incorrect spark plug type can cause
damage to the product.
• Examine the spark plug if the engine is low on
power, is not easy to start or does not operate
correctly at idle speed.
• To decrease the risk of unwanted material on the
spark plug electrodes, obey these instructions:
a) Make sure that the idle speed is correctly
adjusted.
b) Make sure that the fuel mixture is correct.
c) Make sure that the air filter is clean.
• If the spark plug is dirty, clean it and make sure that
the electrode gap is correct, refer to
on page 41 .
• Replace the spark plug if it is necessary.
6.7.3 To do a spark test
1. Remove the spark plug from the cylinder.
2. Connect the spark plug to the spark plug cap.
3. Hold the spark plug against the cylinder and pull the
starter rope handle. If the ignition operates correctly,
a spark occurs between the electrodes on the spark
plug.
4. If no spark occurs, remove the spark plug and
connect the ignition tester (A) to the spark plug cap
(B).
B
C
5. Connect the ground cable (C) to 1 of the cooling fins
on the cylinder.
Technical data
D
A
1425 - 001 - 03.06.2020