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Mercury / Mariner V6 150 / 175 / 200 EFI two-stroke (2.5 L, model year 2002 and newer) service guide

Oil, gear oil, spark plugs and the service schedule for the Mercury / Mariner V6 150 / 175 / 200 EFI two-stroke (2.5 L, model year 2002 and newer) (150 to 200 hp, two-stroke), from the factory service manual, plus how we service it in Hawaiʻi.

Models covered: 150XRI, 175XRI and 200XRI electronic fuel injection V6 two-strokes, starting model year 2002, serial 0T409000 and above (cover): V-6, two cycle, loop charged, 153.0 cu in (2507 cc), bore 3.501 in, stroke 2.650 in, oil injected with the ratio controlled by the ECM, digital inductive ignition.

Quick answers

What two-stroke oil does a Mercury / Mariner V6 150 / 175 / 200 EFI two-stroke use?
Quicksilver or Mercury Precision Lubricants NMMA/BIA certified TC-W3 2 Cycle Outboard Oil.
What is the fuel to oil ratio for a Mercury / Mariner V6 150 / 175 / 200 EFI two-stroke?
Oil injected: gasoline/oil ratio 50:1 (25:1 break-in), ECM controlled, no premix.
What spark plug does a Mercury / Mariner V6 150 / 175 / 200 EFI two-stroke use?
NGK BPZ8HS-10, qty 6. Gap: 0.040 in. (1.0 mm).
How often should a Mercury / Mariner V6 150 / 175 / 200 EFI two-stroke be serviced?
The factory schedule lists: Every 100 hours of use or once yearly, whichever occurs first. In Hawaiʻi's salt water we do a full yearly service every 200 hours or 1 year, whichever comes first, and a new engine needs its first (break-in) service.
When should the water pump impeller be replaced on a Mercury / Mariner V6 150 / 175 / 200 EFI two-stroke?
The factory schedule says to replace it at 100 hours, and we follow that. In any case we never let it go longer than a year in Hawaiʻi's salt water.
What is the idle speed of a Mercury / Mariner V6 150 / 175 / 200 EFI two-stroke?
650 ± 50 RPM in gear; Full throttle 5250 to 5750 RPM.
What is the propeller nut torque on a Mercury / Mariner V6 150 / 175 / 200 EFI two-stroke?
Minimum of 55 lb. ft. (74.5 Nm); bend 3 tabs of the tab washer into the rear thrust hub grooves.

Maintenance specs

Two-stroke engine oilQuicksilver or Mercury Precision Lubricants NMMA/BIA certified TC-W3 2 Cycle Outboard Oil
Fuel to oil ratioOil injected: gasoline/oil ratio 50:1 (25:1 break-in), ECM controlled, no premix
Gear oil quantity22.5 fl oz (665.4 ml) for the 1.87:1 and 2.00:1 gear cases ("approximately 22.5 fl. oz. (665 ml)" in the maintenance section); fill until lubricant flows out of the vent hole with no air bubbles
Gear oil fill/drain plug and vent plugFill/drain plug and vent plug, each with a sealing washer: 60 lb-in (7 Nm). Vent screw in first, then the fill screw
Spark plugNGK BPZ8HS-10, qty 6
Spark plug gap0.040 in. (1.0 mm)
Spark plug torqueFinger tight, then 1/4 turn, or 20 lb-ft (27 Nm)
Idle speed650 ± 50 RPM in gear; Full throttle 5250 to 5750 RPM
Thermostat143 °F (61.7 °C), one in each cylinder head. Water pressure 12 psi minimum at 5500 RPM
Fuel filterReplace the water separating fuel filter
AnodesTwo on the gear case and one on the bottom of the transom bracket: replace before completely eroded; never paint or coat them
Propeller nutMinimum of 55 lb. ft. (74.5 Nm); bend 3 tabs of the tab washer into the rear thrust hub grooves
Power trim fluidPower Trim and Steering Fluid; ATF Type F, FA, Dexron II or Dexron III may be used

Service schedule

The factory maintenance intervals, with what is replaced and what is checked at each. Rows marked Hawaiʻi are our shop's yearly service for salt water use.

  1. Every 100 hours of use or once yearly, whichever occurs first

    Replace: fuel filter, gear case oil, gear case plug gaskets, water pump impeller

    Check: spark plugs, anodes

  2. Every 200 hours or 1 year (our Hawai‘i yearly service) Hawai‘i

    Replace: fuel filter, gear case oil, gear case plug gaskets, water pump impeller

    Check: spark plugs, anodes

Source: Mercury/Mariner 150/175/200 Electronic Fuel Injection service manual, 90-883728, July 2001. Specs can change by model year and serial number, so always confirm your exact model from the serial tag on the clamp bracket.

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