Sierra 18-5870 Stator, Replaces Mercury 398-832075A4, Fits Mercury 90-125 HP Outboards

The Sierra 18-5870 is a marine stator engineered as a direct replacement for the charging-system stator on select Mercury outboard motors. A stator generates the AC current that the outboard's rectifier converts to charge the battery and power the electrical system, making it a core component of the engine's charging circuit. The Sierra 18-5870 is built to meet or exceed the quality and output of the original equipment stator it replaces, using a machined exterior construction designed to hold up to the vibration, heat, and moisture of a harsh marine environment.

This stator fits Mercury 90 HP 3 cylinder electric models, Mercury 100 HP 4 cylinder models, Mercury 115 HP 4 cylinder electric models, and Mercury 125 HP 4 cylinder models, including both domestic and Belgium-built serial number ranges. It is not intended for 4 cylinder models equipped with a voltage regulator, which use a separate Sierra part number. The 18-5870 cross-references to a range of Mercury, Chrysler, CDI, and Mallory OEM stator numbers, so it can be used to replace any of those parts on a covered engine. Always confirm the serial number range and engine configuration of your outboard before ordering to ensure correct fitment.

Specifications

• Brand: Sierra
• Manufacturer Part Number: 18-5870
• Category: Mercury Outboard Stators & Triggers
• Weight: 3.63 pounds
• UPC: 808282112134
• Exterior Finish: Machined
• Dimensions: 0.39 x 0.39 x 0.39 inches
• OEM Cross Reference: 174-832075K2, 398-832075A4, 398-9873A28, 398-9873A19, 9-25507, 398-832075A21

Fitment

• Mercury 90 HP 3 cylinder electric models, serial number G438000 and up
• Mercury 90 HP 3 cylinder electric models (Belgium), serial number 9927000 and up
• Mercury 100 HP 4 cylinder models, serial number G438000 and up
• Mercury 100 HP 4 cylinder models, serial number 9927000 and up
• Mercury 115 HP 4 cylinder electric models, serial number G438000 and up
• Mercury 115 HP 4 cylinder electric models (Belgium), serial number 9927000 and up
• Mercury 125 HP 4 cylinder models, serial number G438000 and up
• Mercury 125 HP 4 cylinder models (Belgium), serial number 9927000 and up

Replaces (OEM)

• 174-832075K2
• 398-832075A4
• 398-9873A28
• 398-9873A19
• 9-25507
• 398-832075A21

Frequently Asked Questions

What Mercury outboards does the Sierra 18-5870 stator fit? The Sierra 18-5870 stator fits Mercury 90 HP 3 cylinder electric models (serial number G438000 and up, or 9927000 and up on Belgium-built units), Mercury 100 HP 4 cylinder models (G438000 and up or 9927000 and up), Mercury 115 HP 4 cylinder electric models (G438000 and up or 9927000 and up), and Mercury 125 HP 4 cylinder models (G438000 and up or 9927000 and up).

Does the 18-5870 stator work on 4 cylinder models with a voltage regulator? No, Mercury 100, 115, and 125 HP 4 cylinder models equipped with a voltage regulator use the Sierra 18-5873 stator, which is a separate part number from the 18-5870.

What OEM part numbers does the Sierra 18-5870 stator replace? The 18-5870 stator cross-references to CDI 174-832075K2, Chrysler 398-832075A4, 398-9873A28, and 398-9873A19, Mallory 9-25507, and Mercury 398-832075A4 and 398-832075A21.

How much does the Sierra 18-5870 stator weigh? The Sierra 18-5870 stator weighs 3.63 pounds.

What is the UPC for the Sierra 18-5870 stator? 808282112134 is the UPC assigned to the Sierra 18-5870 stator.

Is the Sierra 18-5870 a genuine Mercury part or an aftermarket replacement? It is an aftermarket Sierra-brand stator, part number 18-5870, built to meet or exceed the specifications of the original equipment stator it replaces.

What finish does the Sierra 18-5870 stator have? The 18-5870 stator has a machined exterior finish.

Will the 18-5870 stator fit a Mercury 90 HP 6 cylinder outboard? No, the Mercury 90 HP 6 cylinder outboard (serial number 5299506 and up) requires a different stator; the Sierra 18-5870 is built for the 90 HP 3 cylinder electric models.

What are the dimensions of the Sierra 18-5870 stator? The Sierra 18-5870 stator measures 0.39 x 0.39 x 0.39 inches.

Does the Belgium-built Mercury outboard use the same 18-5870 stator? Yes, Belgium-built Mercury 90 HP 3 cylinder, 115 HP 4 cylinder, and 125 HP 4 cylinder electric models with serial number 9927000 and up also use the Sierra 18-5870 stator.

What does a stator like the Sierra 18-5870 actually do on an outboard? The Sierra 18-5870 stator generates the AC current that the outboard's charging system uses to keep the battery charged and power the electrical system.