2003 Honda BF135A / BF150A Outboard Motor Service Manual (P/N 07506-3000001)

• Covers Honda BF135A and BF150A four-stroke outboard motors, including Long (L) and Extra-long (XL) shaft variants with standard and counter-rotation lower units.
• PGM-FI diagnostics provide procedures for reading fault codes and testing circuits with and without the Honda Diagnostic System (HDS).
• Powerhead repair includes engine removal and installation, cam-chain timing, cylinder-head overhaul, and BF150A VTEC rocker-arm testing.
• Gear case service covers water-pump rebuilding, gear and bearing replacement, shim selection, and backlash adjustment.
• Power trim/tilt procedures include cylinder disassembly, seal replacement, air bleeding, and hydraulic pressure checks.
• Starting and charging system repair extends to starter-motor overhaul and alternator rotor, stator, rectifier, and regulator testing.

An official Honda Motor Co., Ltd. publication from November 2003, this shop manual is supplied as a 692-page PDF. Its electrical testing and internal overhaul procedures suit experienced marine mechanics equipped for engine and lower-unit repair. Routine maintenance includes oil and filter changes, valve adjustment, and service of the fuel strainers and water separator.

Type coverage includes LC and LD (L shaft) and XC and XD (XL shaft) with standard rotation. Counter-rotation models are LCD (L) and XCC/XCD (XL). Power trim/tilt is fitted across these types; the remote control box and control panel are optional equipment.

PGM-FI and Warning-System Diagnosis

Diagnostic chapters connect symptoms such as hard starting, rough running, and warning-light activity with component tests. Separate guides cover DTCs and MIL blink codes, while the ECM Terminal Layout identifies connector positions, wire colors, and test conditions. Alert-system charts distinguish oil-pressure, overheating, charging, and water-separator warnings.

Fuel-system procedures include fuel-pressure measurement, injector checks, and vapor-separator overhaul. Idle-air control, intake-air bypass, and A/F sensor feedback also receive dedicated coverage. The specified diagnostic tools include the SCS short connector (070PZ-ZY30100) and test harness (070PZ-ZY60100).

DOHC Powerhead, VTEC, and Cooling

The documentation covers the DOHC cam drive system and cylinder head servicing in detail. Engine repair extends through valve-guide replacement, valve-seat reconditioning, piston and crankshaft inspection, and oil-pump clearance checks. Main and connecting-rod bearing selection uses identification codes and color classifications, with Plastigauge clearance checks.

The BF150A-only VTEC system uses oil pressure to link the intake rocker arms and switch between low- and high-speed cam profiles. A separate compressed-air inspection checks rocker-arm operation using the specified VTEC air adapter (07ZAJ-PNA0101).

Cooling coverage explains the independent cylinder-head and cylinder-block circuits, their separate thermostats, and the Cooling Circuit Diagram. The head-repair section also warns that residual valve-lapping compound can cause severe engine damage.

Gear Case, Power Trim/Tilt, and Controls

Separate gear case procedures distinguish the standard and counter-rotation assemblies. Counter-rotation service includes reverse-gear shim selection and propeller-shaft thrust-clearance adjustment, with drawings showing component orientation.

The Power Trim/Tilt Assembly Quick Reference Chart links hydraulic faults to inspections and replacement decisions. Tilt-motor disassembly and electrical testing are included, but the hydraulic pump is replaced as an assembly if faulty. Steering and control chapters cover swivel-case overhaul, remote-control cable adjustment, and neutral-switch inspection. The linkage notes warn that forcing a shift with the engine stopped can damage the shift system.

Specifications, Exploded Views, and Wiring Diagrams

Specification tables provide internal clearances, gear case oil capacities, valve adjustment settings, and electrical test limits. Cylinder-head tightening instructions distinguish new from reused bolts. Exploded component drawings accompany the repair chapters.

Electrical references include the PGM-FI System Diagram and wiring diagrams for Side Mount Remote Control and Top Mount/Panel Mount Remote Control configurations. These show connector assignments and circuit connections for the controls, engine sensors, relays, and warning equipment.

Working on marine powerheads involves inherent physical risks. Always rely on the complete OEM documentation and proper workshop protocols before beginning any hands-on maintenance or disassembly.