Mercury FourStroke 2.5, Руководство по обслуживанию, Страница: 53 / 205

Ignition
Page 2A-12 90-8M0065421 NOVEMBER 2012
Meter Test Leads
Meter Scale Reading (kΩ)
Red Black
Spark plug lead Black ground wire Ω 10.7–15.7
3. If the reading is other than specified, replace the ignition coil. Refer to
Ignition coil Replacement
.
Checking Ignition Timing
!
WARNING
Moving parts can cause serious injury or death. Wear eye protection and keep hands, hair, and clothing away from moving
parts when performing tests or checking adjustments on an operating engine.
NOTE: The ignition timing is not adjustable. Use a timing light to verify that the ignition timing falls within the timing ranges as
described in the following tests.
IMPORTANT: When checking the timing with the engine running, one of the following test procedures must be followed:
•
In a test tank with a cut down propeller.
• On a boat secured to the trailer in the water with a cut down propeller.
1. Attach the timing light to the spark plug lead.
Timing Light 91‑99379
2. With the outboard in the water, start the engine and allow it to warm up for 2–3 minutes.
3. Operate the engine at idle RPM. Visually check the timing pointer to verify it is within the required timing range on the
flywheel.
NOTE: Each major timing mark equals 10°.
a - 0° flywheel timing mark
b - Pointer on flywheel cover
c - 10° BTDC flywheel timing mark
Ignition Timing
At idle
3° BTDC ± 3°
4. Shift the outboard into forward. Slowly increase the engine speed to 5900–6100 RPM.
5. Visually check the timing pointer to verify the ignition timing advances with the RPM to the wide‑open throttle timing
specification.
Ignition Timing
At wide‑open throttle
25° BTDC ± 3°
41659
a
b
c