Mercury 225 FourStroke EFI 225EXLPT & 225EXXLPT Service Manual 2003 Onwards (P/N 90-888465)

Mercury Marine publication 90-888465, June 2002, covers the 2003 and newer Mercury 225 FourStroke EFI V6 outboard, starting at serial number 0T653945, with 225EXLPT and 225EXXLPT model designations.

This 639-page PDF in English is organized into eight sections, with searchable procedure text and embedded bookmarks.

• EFI diagnosis and repair: Electronic fuel injection theory, fuel-pressure and injector tests, diagnostic flash codes, vapor separator service, and throttle synchronization.

• Ignition, charging and starting: Ignition timing checks, DVA testing, stator and regulator diagnosis, sensor tests, and starter motor overhaul.

• Powerhead repair: Cylinder-head and block/crankcase disassembly, valve clearance adjustment, valve guide and seat work, and crankshaft bearing selection.

• Cooling and lubrication: Water-pump and thermostat inspection, oil-pressure testing, oil-strainer service, and lubrication-system reference drawings.

• Mid-section and power trim: Drive shaft housing and bracket service, trim motor testing, hydraulic diagnosis, cylinder overhaul, and bleeding.

• Lower unit and controls: Separate standard- and counter-rotation gearcase procedures, shimming, backlash measurement, leak testing, and throttle/shift linkage service.

Written for Mercury dealers' mechanics and company service personnel familiar with outboard repair procedures and the required special tools.

EFI and Electrical Fault Finding

The EFI sections follow the low- and high-pressure fuel systems through the fuel rails, pressure regulator, fuel cooler, vapor separator tank (VST), and secondary vapor separator (SVS).

Running problems: The Diagnostic Code Chart and Fail Safe Function Table link sensor faults to changes in ignition, injection, and engine speed. That helps you distinguish an ECM protection response from a separate ignition or fuel-delivery fault.

Hose-routing illustrations cover the VST and both throttle-body banks. The VST repair section identifies collar-bore damage from improper handling as a cause of sticking or poor needle-valve sealing.

Charging and starting: Separate G-G and G/W-G/W stator tests and regulator checks are supported by the Charging System Wiring Diagram and Starting System Wiring Diagram. Tool references include stator test harness 91-804772 and regulator test harness 91-888862.

Ignition timing is ECM-controlled and not adjustable. The manual covers timing verification, throttle shutter synchronization, TPS adjustment, and idle-speed adjustment.

Follow the manual's torque specifications and fuel-pressure release precautions when servicing the fuel system.

Powerhead Rebuilding, Cooling and Lubrication

Compression and cylinder leakage tests include interpretation guidance. Exploded assembly views support powerhead removal and reassembly. Internal repair coverage includes valve shim selection, camshaft and timing-chain inspection, piston and ring measurements, main and connecting-rod bearing selection, and staged tightening sequences.

Torque tables, fluid capacities, compression limits, valve clearances, and wear specifications accompany the procedures.

The crankcase section explains how incorrect bearing placement can produce misleading oil-clearance measurements and engine damage.

Thermostat testing and the Oil Flow Chart support cooling and lubrication diagnosis. The engine oil pump is non-serviceable except for O-ring and seal replacement; its exploded drawing is a component reference.

Drive Shaft Housing and Power Trim

Mid-section coverage includes the oil pan, muffler, steering arm, clamp/swivel brackets, and upper and lower mounts. Power trim repair extends to the gear pump, shuttle and relief valves, memory piston, and trim/tilt cylinders.

The Power Trim System Hydraulic Schematic and Hydraulic System Troubleshooting Flow Chart address leak-down and failure to hold reverse thrust. Relay tests, hydraulic pressure checks, trim-sensor adjustment, and bleeding procedures cover diagnosis and reassembly checks.

Standard- and Counter-Rotation Gearcases

Separate lower-unit sections document bearing-carrier and propeller-shaft service, water-pump repair, and gear setup. The specification tables use F225AET for standard rotation and FL225AET for counter rotation.

Variant-specific shim calculations and backlash checks help you select the setup procedure for the gearcase being rebuilt. The counter-rotation section also includes propeller-shaft shimming. Lubrication data distinguishes the two gearcase capacities and specifies SAE 90 API GL-4 gear oil.

PDF Navigation and Diagram Readability

The total includes one cover, three preliminary pages, three notes pages, six blank or nearly blank pages, and one oversize color wiring sheet. All are already counted in the 639 pages.

Navigation: Bookmarks cover all eight sections and many individual procedures. Some illustration labels are embedded in images and are not searchable as text.

Wiring diagram: The 225 4-Stroke EFI Color Wiring Diagram shows ECM pin locations and color-coded wiring, with its component legend on the preceding page. Small pin and connector numbers are readable when zoomed in.