Mercury Mariner 75-225 HP 4-Stroke Repair Manual 2001-2003

This repair and service manual covers 2001, 2002, 2003 Mercury Mariner 75 HP, 90 HP, 115 HP, and 225 HP four-stroke outboard motors.
Book Excerpt: Mercury Mariner 75-225 HP Four Stroke Repair Manual2001-2003 TROUBLESHOOTING

IDLE AIR CONTROL MOTOR FUNCTION TEST The engine control unit (ECU) controls idle speed using the idle air control motor. The idle air control motor varies air flowing into a dedicated passage in the intake manifold(s). Symptoms of a faulty idle air control motor include stalling when the engine is shifted into gear, too slow or unstable idle, or excessively high idle speed. The engine usually performs correctly at higher speeds. The manufacturer does not provide procedures for testing the idle air control motor. If these symptoms are present, first synchronize and adjust the fuel system components as described in Chapter Four. On 115 hp models, test the shift position switch as described in this section. Replace the idle air control motor as described in Chapter Five if these symptoms persist after the adjustments.

ELECTRICAL AND IGNITION SYSTEMS

OIL PRESSURE SENDER REPLACEMENT The oil pressure sender (Figure 43) is used on 225 hp models. The oil pressure sender is located on front starboard side of the power head and to the rear of the oil filter.

1. Remove the oil filter a described in Chapter Three (see Oil filter replacement).
2. Squeeze the sides, then carefully unplug the engine harness connector from the sender.
3. Engage a wrench onto the hex-shaped section, then unthread and remove the sender.
4. Clean all foreign material from the sender threads and the threaded opening in the power head. Do not allow foreign material to enter the opening. The opening must be clean for proper sealing upon installation.
5. Apply a very light coat of Loctite Pipe Sealand to the threaded section of the sender. Do not allow the sealant to enter the passage into the sender body. Excess sealant may prevent the sender from grounding to the power head and cause it to malfunction.

Subject: 2000, 2001, 2002, 2003 Mercury Mariner 75-225 HP Four Stroke service, maintenance, repair. ISBN-10: 0892878762 | ISBN-13: 9780892878765