1964–1998 OMC Cobra, King Cobra & Stringer Sterndrive Service and Repair Manual

This OMC service and repair manual collection covers 1964–1998 Cobra, King Cobra, and Stringer propulsion systems, with additional sections for SP, SX, SX Cobra, DP, and DP DuoProp drives. Separate engine and drive sections distinguish the older ball-gear systems from later transom-mounted assemblies.

• Engine repair: Engine removal and installation, cylinder-head reconditioning, piston-and-rod service, camshaft and crankshaft work, and valve-train adjustments.

• Sterndrive overhaul: Upper gear housings, lower gearcases, shift converters, intermediate housings, bearing inspection, gear shimming, and backlash adjustment.

• Fuel-system diagnosis: Rochester, Carter, and Holley carburetor service, Ford electronic fuel injection, and GM TBI/MFI troubleshooting with diagnostic trouble-code charts.

• Ignition and electrical systems: Distributor service, electronic ignition tests, starter overhaul, battery and alternator diagnosis, and engine wiring schematics.

• Steering, trim, and tilt: Tru-Course and power steering, SelecTrim mechanisms, hydraulic pump and cylinder service, and trim-system fault tracing.

• Cooling and seasonal care: Water-pump replacement, thermostat testing, exhaust-manifold service, zinc-anode inspection, corrosion protection, and winter-storage preparation.

Boat owners can use the maintenance sections, while marine technicians and experienced owners will need suitable test equipment and mechanical skills for detailed injection diagnosis and drive rebuilding.

Engine Service and Internal Repair

The engine chapters cover GMC in-line engines, Kaiser/GMC 225 and GMC 229 V6 variants, and GM and Ford V8 engines. Later material adds the Ford overhead-cam four-cylinder engine, including timing-belt service.

Removal and installation procedures lead into cylinder-head work, piston-ring inspection, connecting rods, main bearings, rear oil seals, and camshaft service. Hydraulic valve-lifter adjustments, cylinder-head tightening sequences, compression checks, spark-advance charts, and tune-up tables are organized around the applicable engine configuration.

Stringer, Cobra, and DuoProp Drive Work

The Stringer material covers electric-shift units and the 400/800-series arrangements, including shift-converter service, ball gears, swivel housings, exhaust housings, and intermediate-housing boots. Sectional views show how these assemblies fit together.

Later chapters separate standard-rotation and counter-rotation Cobra/King Cobra work from SP/SX and DP procedures. This distinction helps you select the appropriate lower-unit, shimming, and shift-system instructions before disassembly.

Gimbal bearings, U-joints, bellows, and transom assemblies have their own service coverage. SP/SX and DP upper-housing work identifies dedicated tools, including holding fixture 3850605 and retaining-ring spanner 3850604. Gimbal-ring installation notes explain the bearing damage that incorrect seating can cause.

Carburetors and Electronic Fuel Injection

Carburetor coverage includes Rochester BC, 2GC, and 4MV units, Carter RBS, and Holley designs. Disassembly, inspection, reassembly, and bench adjustments are accompanied by component illustrations.

Ford injection diagnosis includes fuel-pressure and leakdown tests, injector checks, and KOEO/KOER self-tests using equipment such as the OMC MFI Tester 500004. GM sections cover TBI and MFI components, diagnostic-link checks, sensor testing, and fault-code charts. Fuel-pressure-regulator section views and MAP-sensor test schematics support the diagnostic text.

The ECM removal section specifically identifies static-discharge damage at the connector pins as a handling risk.

Ignition, Charging, and Wiring References

Distributor service covers Delco-Remy, Mallory, and Autolite/Prestolite equipment. Later sections address EST, BID, Spitfire/EMM, and Ford TFI-IV systems, while starter coverage includes Delco-Remy, Autolite, and Prestolite units.

Battery and alternator tests accompany engine-specific wiring diagrams. Examples include SelecTrim wire-identification drawings and Ford-engine wiring schematics showing the shift-assist circuit, charging connections, and instrument senders.

Cooling, Steering, and Trim Service

Cooling chapters cover raw-water pumps, circulating pumps, thermostats, exhaust manifolds, and system testing. Maintenance material also addresses below-waterline service, zinc anodes, corrosion control, and seasonal draining.

Tru-Course steering, mechanical steering, and power-assist systems are treated alongside SelecTrim hydraulics and later power trim/tilt assemblies. Older tilt-mechanism coverage includes the hammer blow coupling, tilt clutch, and worm gear.

Follow the manual's precautions for fuel vapor, electrical isolation, and lifting engine or drive assemblies, and use qualified marine help for work beyond your training.

A Preview of Injection Pressure Specifications

These examples show a small part of the fuel-system test data in the manual.

For the GM 1994–96 no-start diagnostic checks, the listed pressure is 9–13 psi for TBI engines and 36–42 psi for MFI engines, with the ignition on and the fuel pump running. The separate test ranges help distinguish the two injection systems; later configurations have their own specifications.

Text Search, Bookmarks, and PDF Contents

Finding procedures and reading diagrams: The PDF has an OCR text layer and embedded bookmarks for both manual sections. Search coverage is incomplete, particularly on some tables, chapter-opening pages, and wiring sheets. Small wiring labels require enlargement; some older diagram lines are faint.

The download is one printable, 1,183-page PDF containing a 572-page earlier manual and a 611-page later manual. The total already includes seven main contents pages, the earlier manual's 97-page appendix, six master-index pages, and the one-page Engine Finder.