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Mercury / Mariner V6 135 / 150 / 175 / 200 two-stroke, carbureted and EFI (serial 0G960500 and above) service guide

Oil, gear oil, spark plugs and the service schedule for the Mercury / Mariner V6 135 / 150 / 175 / 200 two-stroke, carbureted and EFI (serial 0G960500 and above) (135 to 200 hp, two-stroke), from the factory service manual, plus how we service it in Hawaiʻi.

Models covered: V6 two-strokes, loop charged, oil injected: 135, 150 XR6 / Magnum III and 200 (carbureted), serial 0G960500 and above; 150XRI, 175XRI and 200XRI (EFI), serial 0G960500 to 0T408999. The 135 is 121.9 cu in (1998 cc), bore 3.125 in; the XR6 / Mag III, 200 and the XRI models are 153.0 cu in (2507 cc), bore 3.501 in; stroke 2.650 in.

Quick answers

What two-stroke oil does a Mercury / Mariner V6 135 / 150 / 175 / 200 two-stroke, carbureted and EFI use?
TC-W3 2 Cycle Outboard Oil only.
What is the fuel to oil ratio for a Mercury / Mariner V6 135 / 150 / 175 / 200 two-stroke, carbureted and EFI?
Oil injected: gasoline with oil injection, gasoline/oil ratio 50:1 (25:1 break-in).
What spark plug does a Mercury / Mariner V6 135 / 150 / 175 / 200 two-stroke, carbureted and EFI use?
NGK BPZ8HS-10, qty 6, the same for carbureted and EFI models. Gap: 0.040 in. (1.0 mm).
How often should a Mercury / Mariner V6 135 / 150 / 175 / 200 two-stroke, carbureted and EFI 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 135 / 150 / 175 / 200 two-stroke, carbureted and EFI?
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 135 / 150 / 175 / 200 two-stroke, carbureted and EFI?
Carbureted: 650 ± 50 RPM (135 / 200), 675 ± 50 RPM (XR6 / Mag III). EFI: 650 ± 50 RPM. Idle mixture screw preset 1-1/2 ± 1/8 turns out (135), 1-1/4 ± 1/8 (150 / 200), not adjustable on EFI.
What is the propeller nut torque on a Mercury / Mariner V6 135 / 150 / 175 / 200 two-stroke, carbureted and EFI?
Minimum of 55 lb. ft. (74.5 Nm); bend 3 tabs of the tab washer into the rear thrust hub grooves; retighten after first use.

Maintenance specs

Two-stroke engine oilTC-W3 2 Cycle Outboard Oil only
Fuel to oil ratioOil injected: gasoline with oil injection, gasoline/oil ratio 50:1 (25:1 break-in)
Gear oil quantity22.5 fl oz (665.4 ml) for the 1.87:1, 2.00:1 and 2.30:1 gear cases ("approximately 22.5 fl. oz. (665 ml)" in the maintenance section); add until lubricant appears at the vent hole
Gear oil fill/drain plug and vent plugFill/drain plug and vent plug, each with a sealing washer: 60 lb-in (7 Nm). Install the vent plug before removing the lubricant tube, then the fill/drain plug; replace sealing washers if damaged (the gear housing section says install new gaskets)
Spark plugNGK BPZ8HS-10, qty 6, the same for carbureted and EFI models
Spark plug gap0.040 in. (1.0 mm)
Spark plug torqueFinger tight, then 1/4 turn, or 20 lb. ft. (27 Nm)
Idle speedCarbureted: 650 ± 50 RPM (135 / 200), 675 ± 50 RPM (XR6 / Mag III). EFI: 650 ± 50 RPM. Idle mixture screw preset 1-1/2 ± 1/8 turns out (135), 1-1/4 ± 1/8 (150 / 200), not adjustable on EFI
Thermostat143 °F (61.7 °C), one in each cylinder head. Water pressure 12 psi minimum at 5500 RPM
Fuel filterCarbureted models: check the engine fuel filter for contaminants. EFI models: replace the water separating fuel filter (spin-on, hand tight, oil the sealing ring)
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; retighten after first use
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 135/150/175/200 HP service manual, 90-878079R01, August 2002. 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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