Water in Fuel / Water Separator Sensor for Mercury & Mariner Outboards

Marine-grade aftermarket water-in-fuel (WIF) sensor for selected Mercury and Mariner outboards.

The sensor detects water contamination in the fuel system / water-separating fuel filter and allows the engine monitoring system to provide a warning.

Replaces Mercury 889330 / 8M0021043.

Fitment

Fits selected Mercury / Mariner applications including:

DFI / OptiMax

75 HP
80 Jet
90 HP
115 HP
115 Pro XS
125 HP
200 HP
225 HP
250 HP

4-Stroke EFI

Selected:

65 HP
75 HP
80 HP
90 HP
100 HP
115 HP
135 HP
150 HP

Verado

Selected:

135 HP
150 HP
175 HP
200 HP
225 HP
250 HP
275 HP
300 HP
350 HP
400 HP

Also used on selected Mercury Racing and Zeus applications.

Replaces Mercury Part Numbers

889330
8M0021043

Current Mercury Supersession

8M0214989

Mercury 889330 was superseded by 8M0021043, which has subsequently been superseded by 8M0214989.

The latest replacement may look different from the original sensor but is listed as the functional replacement.

Additional Cross References

Sierra 18-7606
MAR-10171-30-00
AM8M0021043

Product Function

This sensor is fitted to applicable water-separating fuel filter / vapor separator systems.

It monitors for the presence of water in the fuel and sends the appropriate signal to the engine monitoring system.

A water-in-fuel warning should be investigated promptly, as contaminated fuel can cause poor running and damage to fuel-system components.

Product Features

Water-in-fuel sensor
Fuel & water sensor
Water separator sensor
Mercury / Mariner applications
Selected DFI / OptiMax
Selected 4-Stroke EFI
Selected Verado
Marine-grade aftermarket replacement
New

What's Included

1 × Water in Fuel Sensor

⚠️ Important Compatibility Warning

This sensor does NOT fit every Mercury / Mariner engine within the horsepower or year ranges listed.

Please check:

Original sensor part number
Engine horsepower
Engine model
Complete serial number
Electrical connector
Fuel filter / vapor separator configuration

If the part looks the same as yours, this does not always mean it is the correct part for your outboard.

If unsure, send SSI Marine your engine horsepower + complete serial number + original sensor number and we will help check compatibility.

Buyer Responsibility

It is the buyer's responsibility to confirm compatibility before purchasing.

OEM part numbers are used for identification and reference purposes only.

Why Buy From SSI Marine?

Marine-grade aftermarket & OEM-spec parts
Workshop-tested products
More than 10 years supplying outboard parts
Same-day dispatch before 1 PM Monday–Friday
Royal Mail Tracked 24
UK stock
Collection from Leigh, Greater Manchester
Technical support from experienced outboard specialists

65-400 HP Mercury Mariner Outboard Water in Fuel Sensor 8M0021043 889330