6J4-81800-01 Aftermarket Yamaha Mercury 40HP Outboard Starter Motor (1986-92) | Sawley's Select Marine Parts

🔧 Product Description

Aftermarket Yamaha / Mercury-Mariner 30-50HP Outboard Starter Motor - Part Number: 6J4-81800-01

New aftermarket 11-tooth counter-clockwise starter for Yamaha-built 30HP, 40HP and 50HP outboards. Mercury and Mariner applications must use the corresponding 50-814980M starter reference; the 6J4 number alone must not be used to identify a Mercury-built powerhead.

⚙️ Key Features

• 12-volt marine electrical system

• Counter-clockwise rotation viewed from the drive end

• 11-tooth starter pinion

• Direct-drive marine starter construction

• Integrated solenoid and overrunning clutch

• Expanded Yamaha application range beyond the 40HP wording in the supplied title

🧰 Assembly Contents

• 1 × Complete starter motor assembly - Part Number: 6J4-81800-01

• 1 × Integrated starter solenoid

• 1 × Installed 11-tooth pinion and overrunning clutch

• 1 × Installed armature, field assembly, brush holder and starter housing

• Mounting hardware and external wiring are supplied separately unless stated

🔄 Supersession & Cross Reference

OEM Supersession Chain:

• 6J4-81800-01 → Supersedes 6J4-81800-00

• 6J4-81800-00 → Earlier Yamaha complete starter reference

OEM / Related Numbers:

• 6J4-81800-01

• 6J4-81800-01-00

• 6J4-81800-00

• 6F5-81800-10

• 6F5-81800-11

• Mercury / Mariner 50-814980M

• Hitachi S108-87A

Aftermarket / Verified Equivalents:

• Sierra Marine: 18-6421

• ARCO Marine: 3423

• API Marine: MOT5014N-AM

• Recmar: REC6J4-81800-01

• Hitachi: S108-87A

🚤 Compatibility

Commonly used on:

• Yamaha-built mid-range two-stroke outboard starting systems

Typically suits:

• Yamaha 30HP model families from approximately 1987 onward using the 6J4 starter

• Yamaha 40HP and 50HP model families from approximately 1989 onward using the 6J4 starter

• Mercury/Mariner 40HP engines within the supplied 1986-1992 period only where the original starter cross-references to 50-814980M or 6J4-81800-01

• HP Range: 30-50 HP

• Engine Type: Two- or three-cylinder carburetted two-stroke outboard, model dependent

• Year Range: Approximately 1987-2006 for Yamaha applications; Mercury/Mariner fitment is OEM-number controlled

• Serial / Model Identification: Confirm 11 teeth, counter-clockwise rotation, mounting pattern and the removed starter number. Do not substitute for the earlier 9-tooth 6H4 starter.

🔌 Function

Provides the initial crankshaft rotation required for starting. The 11-tooth pinion must mesh with the matching flywheel ring gear and the starter nose must align squarely with the engine bracket.

Common signs of failure:

• No-crank condition with correct battery and control-circuit voltage

• Slow cranking or high current draw

• Pinion spins without engaging

• Grinding caused by incorrect tooth count or mounting alignment

• Intermittent operation from worn brushes or solenoid contacts

• Corrosion, heat damage or excessive bearing/bushing wear

📦 Condition

• Brand-new aftermarket replacement starter motor

• New and unused

• Supplied in suitable manufacturer or equivalent protective packaging