18736A21 Mercury Voltage Regulator | Genuine Used Part

🔧 Product Description

Genuine Mercury Dual Voltage Regulator Kit - Part Number: 18736A21

A genuine Mercury voltage regulator reference used on V6 two-stroke outboard charging systems. This regulator is commonly associated with 40 amp six-cylinder Mercury / Mariner charging systems and cross-references with dual-regulator aftermarket kits for engines requiring four yellow wire stators.

⚙️ Key Features

• Genuine Mercury voltage regulator reference
• Correct Mercury part number 18736A21
• Related to earlier Mercury regulator references 18736A8 and 18736A11
• Used on V6 two-stroke Mercury / Mariner 135HP to 200HP charging systems where specified
• Charging-system component requiring exact stator wire configuration and parts-diagram confirmation

🚤 Compatibility

Commonly used on

• Mercury / Mariner V6 two-stroke 40 amp charging systems using the 18736A21 regulator family

Typically suits

• Engine models:
• Mercury 135HP V6 two-stroke 1989-1991 charging systems with 40 amp output and four yellow wire stator configuration
• Mercury 150HP V6 two-stroke 1989-1991 charging systems with 40 amp output and four yellow wire stator configuration
• Mercury 175HP V6 two-stroke 1989-1991 charging systems with 40 amp output and four yellow wire stator configuration
• Mercury 200HP V6 two-stroke 1989-1991 charging systems with 40 amp output and four yellow wire stator configuration
• Mariner 135HP / 150HP / 175HP / 200HP V6 two-stroke applications using the same 18736A21 dual-regulator charging-system family
• HP Range: 135HP - 200HP
• Engine Type: Mercury / Mariner V6 two-stroke outboard
• Year Range: 1989 - 1991 for core 40 amp V6 charging-system applications
• Charging System: 40 amp, six-cylinder, four yellow wire stator configuration

🔌 Function

The voltage regulator / rectifier converts AC stator output to DC charging voltage and regulates that output to protect the battery, ignition electronics and vessel electrical system.

⚠️ Common Signs of Failure

• Battery not charging while engine is running
• Charging voltage too high or unstable
• Tachometer drop-out caused by charging circuit faults
• Regulator overheating or melted wiring
• Blown charging-system fuse or repeated battery issues
• Burnt yellow stator wires or damaged regulator connectors
• Electrical accessories cutting out due to voltage fluctuation

🔄 Supersession & Cross Reference

OEM Supersession Chain

• 18736A21 current / later Mercury voltage regulator reference
• 18736A11 earlier related voltage regulator reference
• 18736A8 earlier related voltage regulator reference

OEM / Related Numbers

• 18736A21
• 18736A20
• 18736A11
• 18736A8
• 194-1873
• 174-9610A18
• 194-8736K 1
• 194-5279R component regulator reference
• Related 40 amp six-cylinder regulator / rectifier charging-system family

Aftermarket / Verified Equivalents

• CDI Electronics: 194-8736K 1
• CDI Electronics: 194-5279R component regulators
• WSM / aftermarket conversion family: 174-9610A18
• Aftermarket replacement reference: 194-1873

📦 Condition

• Genuine used part
• Removed from running engine where applicable
• In good working condition unless otherwise stated