John Deere 318 - Manual (Page 327)

3b
Ignition Circuit
Test—For
Machines
(S.N. —420000)
Disconnect spark plug
wires and remove spark
plugs.
Connect a spark tester
to each of the spark
plug wires.
M77904 -UN-19JAN95
Connect a jumper wire
from positive (+) battery
terminal to positive (+)
coil terminal (A). Crank
engine and check for
spark. SPARK: Wire between
ignition coil positive (+)
terminal and 3-pin
engine connector is
open or 3-pin engine
connector is faulty.
NO SPARK: GO TO
3c
3c
Ignition Points:
Inspection and
Adjustment—
For Machines
(S.N. —420000)
Disconnect negative
(—) battery cable.
Remove ignition points
cover.
Inspect points for
burning, pitting or other
damage.
If points are damaged,
replace them as
instructed in CTM2.
M55083 -UN-09DEC89
M78973 -UN-16MAY95
Turn engine by rotating U-joint until ignition
points are at widest gap.
Check point gap using a feeler gauge.
Turn adjusting screw (A) until gap is set to
specifications.
IGNITION POINT GAP SPECIFICATIONS
B43E and B43G . . . . . . . . . . . . 0.41 mm (0.016 in.)
B48G
Spec A and B . . . . . . . . . . . . 0.51 mm (0.020 in.)
Spec C . . . . . . . . . . . . . . . . 0.41 mm (0.016 in.)
AFTER REPAIR OR
ADJUSTMENT: GO TO
Æ
, Group 05.
IF STILL NO SPARK:
GO TO
3d
3d
Ignition Coil Test:
Primary Windings—
For Machines
(S.N. —420000)
Key switch OFF.
Disconnect all wires
from ignition coil.
M77939 -UN-19JAN95
Using a ohmmeter,
measure resistance of
primary windings across
terminals (A).
Resistance should be
3.9—4.7 ohms when
temperature of coil is
approximately 20˚C
(68˚F).
RESISTANCE OK: GO
TO
3e
RESISTANCE NOT
OK: Replace coil.
MX,159024025,42-19-16MAY95
MX,159024025,43-19-16MAY95
MX,159024025,45-19-16MAY95
Electrical System Diagnosis/Ignition Circuit Tests
TM1590 (17MAY95)
240-20-15
316, 318 & 420 Lawn and Garden Tractors
020895
240
20
15