Sierra 18-99225 Red Stator for Mercury/Mariner 6-25 HP Outboards, Replaces 855721A4

The Sierra 18-99225 is a red stator built to power the ignition system on compatible Mercury and Mariner outboard engines. The stator mounts under the flywheel and generates the electrical current the ignition system needs to fire the spark plugs, making it a core component for engines that will not start or run erratically due to a failed or weakening charging coil. This is a direct-fit replacement stator, engineered to restore reliable spark output without modification to the surrounding ignition components.

This stator is designed for Mercury/Mariner 2-stroke outboard engines equipped with four-magnet flywheels, covering the 6, 8, 9.9, 10, 15, 20 and 25 HP engine range built in the 1997-2005 span. It is identified by its red housing color, a visual cue used to distinguish it from other stator variants in the Mercury/Mariner lineup, so confirming the red color along with the horsepower and flywheel type helps ensure correct fitment before ordering.

Specifications

• Brand: Sierra
• Manufacturer Part Number: 18-99225
• Color: Red
• Weight: 0.7 pounds
• UPC: 808282393922
• Category: Mercury Outboard Stators & Triggers
• Engine Fitment: Mercury/Mariner 2-stroke outboards with four-magnet flywheels, 6, 8, 9.9, 10, 15, 20 and 25 HP (1997-2005)
• OEM Cross Reference: 855721A4, 855721T8, 721851

Fitment

• Mercury/Mariner 2-stroke outboards, 6, 8, 9.9, 10, 15, 20 and 25 HP, with four-magnet flywheels (1997-2005)

Replaces (OEM)

• 855721A4
• 855721T8
• 721851

Frequently Asked Questions

What engines does the Sierra 18-99225 stator fit? It fits Mercury/Mariner 2-stroke outboards with four-magnet flywheels in the 6, 8, 9.9, 10, 15, 20 and 25 HP range, built in the 1997-2005 span.

What color is the 18-99225 stator? Red. The red housing is a visual identifier used to distinguish this stator variant from other Mercury/Mariner stator styles.

What OEM part numbers does this stator replace? The Sierra 18-99225 replaces Mercury/Mariner OEM numbers 855721A4, 855721T8, and 721851.

How much does the 18-99225 stator weigh? This stator weighs 0.7 pounds.

Does this stator work on 4-stroke Mercury outboards? No. The 18-99225 is built for 2-stroke Mercury/Mariner outboards with four-magnet flywheels, not 4-stroke engines.

How do I know if my flywheel is compatible? The 18-99225 is designed for four-magnet flywheel setups, so confirming your flywheel has four magnets alongside your engine's horsepower rating is the key fitment check.

Is the 18-99225 a direct OEM replacement? Yes, it is a direct-fit replacement stator that installs in place of the original Mercury/Mariner unit without modification.

What are the symptoms of a failing stator that this part fixes? A failing stator on these Mercury/Mariner outboards typically causes hard starting, weak or intermittent spark, or the engine stalling and refusing to restart; the 18-99225 restores the ignition charging function.

Does the stator come with mounting hardware? The listing covers the Sierra 18-99225 stator itself; check your engine's original hardware for reuse during installation.

What horsepower range covers the 18-99225? It covers Mercury/Mariner 6, 8, 9.9, 10, 15, 20 and 25 HP outboards equipped with four-magnet flywheels.