Honda BF40D Owner's Manual page 77

SIDE ELECTRODE
0.024
−
(0.6
SEALING WASHER
INSULATOR
5. Measure the spark plug electrode
gap with a wire-type feeler gauge.
Correct the gap, if necessary, by
carefully bending the side
electrode.
The gap should be:
0.024 0.028 in −
(0.6 0.7 mm) −
− 0.028 in
0.7 mm)
6. Install the spark plugs carefully,
by hand, to avoid cross-threading.
SERVICING YOUR OUTBOARD MOTOR
7.
8.
9.
After each spark plug seats, tighten
with a spark plug wrench to
compress the sealing washer.
If reinstalling used spark plugs,
−
tighten 1/8 1/4 turn after the
spark plugs seat.
If installing new spark plugs,
tighten 1/2 turn after the spark
plugs seat.
Loose spark plugs can overheat
and damage the engine.
Overtightening the spark plugs
can damage the threads in the
cylinder head.
Attach the spark plug caps.
Install and lock the engine cover.
75