Makita PM7651H Technical Information page 21

6-9-3 Checking of Ignition coil
For checking troubles in Ignition System of Gasoline engines. Set it between Plug cap and Plug to check the state of ignition.
Note:
Do not remove Spark plug.
·
It is necessary to check the sparks generate certainly by pulling Starter rope against the compressed air in Cylinder for normal
·
use. A way that you find the sparks with Spark plug attached on outside of Cylinder directly is prohibited.
Persons who use a pacemaker must not handle 1R181.
·
When Blade is set in place for checking Ignition coil, full attention is required.
·
Dangerous high voltage comes to each terminal of electric parts during use,
·
and therefore, do not touch them.
Check that the terminals of 1R181 are firmly tightened. (See Fig. 6-9-3-1)
·
Do not tighten [Spark distance adjusting knob] too much over the specific torque.
·
First, check the behavior at engine start as the following order.
[3] Remove Spark plug cap with
Cable from Spark plug on
Cylinder, and then connect the cap
to 1R181.
Note: When you find it difficult to see the sparks in
Spark window, adjust the brightness to darker.
[4] Pull Starter rope quickly ten times continuously and check that sparks (whose color is more pale than Spark window)
can be certainly seen at each time.
It is because some Ignition coils start to transmit the electricity when the certain rpm is obtained.
In case the sparks cannot be seen once or more in ten times, replace Ignition coil with a new one.
Note: Above is a basic check of Ignition coil. When the result is good and the engine runs without any abnormalities, the
additional check for Ignition coil shown in the next page can be skipped.
[1] Attach Alligator
Cylinder fin
Cable from Ignition
coil
Spark window
Fig. 6-9-3-2
[2] Turn Spark distance adjusting
clip to Cylinder fin.
Note: Some products
have this
projection on the
top.
21 / 41
Fig. 6-9-3-1
Terminals of
1R181
knob so that the spark distance in
Spark window shows 6mm.
Contents of 1R181
Spark distance
adjusting knob
Low voltage
terminal
High voltage
terminal
Plug cap
Cable
Alligator clip