This repair manual covers 2001 to 2009 Mercury Outboard 2.5 HP to 250 HP, 1-4 cylinder and V6 2-stroke motors, including Jet Drives.
Step-by-step illustrated keyed procedures guide you through every conceivable job possible, including all adjustments necessary. Perfect for do-it-yourselfers, professional mechanics, or students.
Book Excerpt: 2001-2009 Mercury 2.5-250 HP, 1-4 Cylinder & V-6 2-Stroke Repair Manual
TROUBLESHOOTING THE IGNITION SYSTEM
SPARK PLUGS & CHECKING FOR SPARK
TABLE of CONTENTS:
The absolute first thing that you should check when an ignition problem is suspected is the spark plugs. You want to determine that the plugs (the most common wear item in an electronic system) are in good condition and are producing a good, strong spark.
Likewise, a spark check should be conducted using some form of an inexpensive spark checking tool which either installs inline between the secondary ignition wire (spark plug wire) and the spark
plug itself, OR substitutes for the spark plug.
- Check the plug wires to be sure they are properly connected. Check the entire length of the wires from the plug(s) back to the coil(s).
If a wire is to be removed from the spark plug, always use a pulling and twisting motion as a precaution against damaging the connection.
- Attempt to remove the spark plug by hand. This is a rough test to determine if the plug is tightened properly. The attempt to loosen the plug by hand should fail.
The plug should be tight and require the proper socket size tool. Remove the spark plug and evaluate its condition. Reinstall the spark plug and tighten to the proper specification.
- Use a spark tester and check for spark. If a spark tester is not available (and for Pete's sake they're cheap and can be found in almost all auto part stores) hold the plug wire about 1/4 in. (6.4mm) from the engine (leave the
plug in the port for safety).
Carefully operate the starter and check for spark.A strong blue spark over a wide gap must be observed when testing in this manner, because under compression a strong spark is necessary in order to ignite the air-fuel mixture in the cylinder.
This means it is possible to think a strong spark is present, when in reality the spark will be too weak when the plug is installed.
If there is no spark, or if the spark is weak (orange), the trouble is most likely under the flywheel.
- General information
- Tools and equipment
- Boating safety
- Engine tune-up
- Engine disassembly and reassembly
- Fuel system
- Oil injection system
- Cooling system
- Cooling system flow schematics
- Ignition system
- Powerhead mechanical
- Powerhead reconditioning
- Powerhead break-in
- Lower unit
- Jet Drive
- Electrical system
- Mechanical tilt (unassisted)
- Gas assist tilt system
- Power tilt/trim
- Remote controls
- Hand rewind starter
- Engine specs; torque specs
- Maintenance and off-season storage
- Wiring diagrams
Subject: 2001, 2002, 2003, 2004, 2005, 2006, 2007, 2008, 2009 Mercury 2.5-250 HP, 1-4 Cylinder and V-6 2-Stroke service, maintenance, repair. ISBN-10: 0893300675 | ISBN-13: 9780893300678 | Seloc 1418