Mercury / Mariner 25–30 HP Outboard Service Kit – 100 / 300 Hour Maintenance – EFI 4-Stroke

Complete service and maintenance kits for selected Mercury / Mariner 25 HP and 30 HP EFI 4-stroke, 3-cylinder outboard engines, manufactured by Tohatsu.

Assembled by SSI Marine using our marine workshop experience, these kits are available in three service options, allowing you to choose the maintenance package that suits your requirements.

Engine Compatibility – UK & European Models

Engine serial-number family: 0R106999–1R162636

The original Tohatsu-manufactured engine family overlaps with the introduction of the redesigned Mercury 500 cc engines in 2022. For this reason, engines from serial 1R154758 onwards require additional confirmation of the original 526 cc platform.

Not suitable for earlier carburettor engines, 25 HP Jet models or the newer 500 cc Mercury EFI engines.

Choose Your Service Kit

Select your preferred service option from the product variants before adding to your basket.

Variant 1 – 100 Hour Service Kit

Ideal for routine servicing, including engine oil, gearbox oil, filters, spark plugs and water pump impeller.

Includes:

• 2 × 1 L Rock Oil MP+ Sport 10W40 Engine Oil

• 1 × 1 L Rock Oil MP Marine Gear Oil

• 1 × Engine Oil Filter

• 1 × Fuel Filter

• 3 × NGK DCPR6E Spark Plugs

• 2 × Gearbox Drain / Fill Plug Gaskets

• 1 × Water Pump Impeller

Variant 2 – 300 Hour Full Service Kit

Our comprehensive maintenance package, including all the 100-hour service components plus additional cooling system, water pump and corrosion protection parts.

Includes everything in the 100 Hour Kit, plus:

• 2 × Water Pump Gaskets

• 1 × Thermostat

• 1 × Thermostat Gasket

• 1 × Trim Tab Anode

• 1 × Power Trim / Tilt Anode

• 1 × Rock Oil Marine Grease

• 1 × Gear Oil Filling Pump

Variant 3 – 300 Hour Service Kit – No Oils

The comprehensive 300-hour maintenance package for customers who already have their own lubricants.

Includes:

• 1 × Engine Oil Filter

• 1 × Fuel Filter

• 3 × NGK DCPR6E Spark Plugs

• 2 × Gearbox Drain / Fill Plug Gaskets

• 1 × Water Pump Impeller

• 2 × Water Pump Gaskets

• 1 × Thermostat

• 1 × Thermostat Gasket

• 1 × Trim Tab Anode

• 1 × Power Trim / Tilt Anode

This variant does NOT include engine oil, gearbox oil, marine grease or a gear oil filling pump.

Important Compatibility Information

These kits are intended for the original Tohatsu-manufactured Mercury / Mariner 25–30 HP EFI 526 cc 3-cylinder engines.

Please check your engine serial number and engine type before ordering, especially on 2022 models where the engine design changed.

The power trim / tilt anode is intended for engines fitted with the compatible PTT system. Check the anode arrangement on your engine before selecting a kit.

The 100-hour and 300-hour labels describe the kit options; always follow your engine manufacturer's maintenance schedule for the correct service intervals.

If the part looks the same, it is not always the right one for your outboard.

Why Buy From SSI Marine?

• Service kits assembled using over 20 years of marine engineering experience

• Over 10,000 genuine and aftermarket outboard parts stocked in the UK

• Same-day dispatch for orders placed before 1 PM Monday–Friday

• Royal Mail Tracked 24 UK delivery

• Collection available from Leigh, Greater Manchester

• Technical support from experienced marine engineers

• Celebrating 10 years supplying the UK marine market

SSI Marine – Outboard Parts, Servicing & Marine Engineering

Buyer Responsibility: Please confirm your engine model, serial number and gearbox/anode configuration before purchasing.