Inspecting Ignition Coil Resistance; Replacing Spark Plug Cap And Coil - Yamabiko ECHO SRM-420ES Service Manual

SRM-420ES, SRM-420TES
T410S, B410S
T410TS, B410TS

3-6 Inspecting ignition coil resistance

D

3-7 Replacing spark plug cap and coil

A
IGNITION SYSTEM
A
C
B
B
A
C
1. Remove starter assembly (Refer to "2-1 Disas-
sembling starter assembly). Remove inner cylinder
cover and fan cover.
2. Connect one probe of Ohm-meter or multimeter
to spark plug cap coil (A).
3. Connect the other probe to cylinder fin (B) to
measure secondary coil resistance. Secondary
coil resistance should be in the range of 930 to 970
Ω.
4. I f t h e m e t e r r e a d i n g i n d i c a t e s i n fi n i t e
re s i s ta n c e , remove spark plug cap and spark
plug cap coil, and measure resistance between the
conduction wire of high tension lead and ignition
coil core.
5. Keep probe (C) on cylinder fin (B). Remove
probe (D) from spark plug cap coil (A) and connect
probe (D) to ignition coil core to confi rm that the
circuit is in conducting state (closed circuit). If the
circuit is not in conducting state, ensure conduction
between ignition coil bolt and cylinder.
6. If the reading at step 3 or 4 is not in the range of
the above, replace with a new ignition coil (Go to
"3-8 Replacing ignition coil").
1. Disconnect spark plug cap (A) from spark plug.
2. Apply some oil in spark plug cap (A) for easy re-
moval from high tension lead (B).
3. Pull spark plug cap (A) away from high tension
lead (B).
4. Inspect spark plug cap coil (C) for corrosion
and correct connection. Inspect spark plug cap for
cracks. Replace them as required.
NOTE: Make sure spark plug cap coil (C) contacts
center core of high tension lead when reinstalling
it.
5. Coat end of high tension lead (B) with small
amount of oil, and insert it into spark plug cap (A)
as shown until the spark plug cap coil is properly
seated in the cap.
B
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