Tohatsu MD115A TLDI (4 cylinder, 1,768 cc, direct injection two-stroke) service guide

Quick answers

What two-stroke oil does a Tohatsu MD115A TLDI use?

Genuine MD oil: oil for two stroke direct injection engines recommended by the outboard manufacturer.

What gear oil does a Tohatsu MD115A TLDI use, and how much?

Hypoid gear oil, API GL-5, SAE #90. Quantity: 900 cm3 (30.4 fl oz).

What spark plug does a Tohatsu MD115A TLDI use?

NGK IZFR5J, qty 4. Gap: 0.7 to 0.8 mm (0.029 to 0.032 in), functional limit 0.9 mm (0.036 in).

How often should a Tohatsu MD115A TLDI be serviced?

The factory schedule lists: Initial 20 hours or initial 1 month; At 50 hours or every 3 months; At 100 hours or every 6 months; At 200 hours or every year; Every 2 years, done with every second yearly service. 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 Tohatsu MD115A TLDI?

The factory schedule says to replace it at 200 hours and 400 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 Tohatsu MD115A TLDI?

700 / 800 / 900 r/min, in neutral and in forward.

Maintenance specs

Injection (two-stroke) oil	Genuine MD oil: oil for two stroke direct injection engines recommended by the outboard manufacturer
Oil tank	6.7 L (1.77 gal); electric oil pump under ECU control
Gear oil	Hypoid gear oil, API GL-5, SAE #90
Gear oil quantity	900 cm3 (30.4 fl oz)
Gear oil drain and level plugs (lower and upper oil plug)	Remove the lower oil plug first, then the upper; fill through the lower hole until oil comes from the upper hole; fit the upper plug first. New gasket on both plugs (do not reuse)
Gear case pressure test	0.05 MPa (7 psi, 0.5 kgf/cm2)
Spark plug	NGK IZFR5J, qty 4
Spark plug gap	0.7 to 0.8 mm (0.029 to 0.032 in), functional limit 0.9 mm (0.036 in)
Spark plug torque	25 N·m (18 lb-ft, 2.5 kgf·m)
Idle / trolling speed	700 / 800 / 900 r/min, in neutral and in forward
Thermostat	With wax type pressure relief valve: valve opening temperature 58.5 to 61.5 °C (137 to 143 °F), listed as 60 °C (140 °F) in the maintenance data; full-open 75 °C (167 °F) or higher; valve lift 4.5 mm (0.177 in) or more at 75 °C
Fuel filters	Fuel filter: inspection and filter cleaning. High pressure fuel filter: cartridge type. Air compressor air filter: inspected at 200 hours, replaced every 2 years
Power trim and tilt fluid	ATF Dexron III
Air compressor drive belt	Tension 100 to 230 N (Unitta tension gauge); deflection 4 to 6 mm (0.16 to 0.24 in) when pushed with 20 N, adjusted cold by moving the compressor. Replace if worn, damaged, cracked, chipped or oily. Driven pulley nut 50 N·m; drive pulley (flywheel nut) 260 N·m

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. Initial 20 hours or initial 1 month

   Replace: gear case oil, gear case plug gaskets, propeller cotter pin

   Check: spark plugs, fuel filter

2. At 50 hours or every 3 months

   Replace: gear case plug gaskets, propeller cotter pin

   Check: fuel filter, gear case oil, water pump impeller, anodes

3. At 100 hours or every 6 months

   Replace: gear case oil, gear case plug gaskets, propeller cotter pin

   Check: spark plugs, fuel filter, water pump impeller, thermostat, anodes

4. At 200 hours or every year

   Replace: gear case oil, gear case plug gaskets, propeller cotter pin, water pump impeller

   Check: spark plugs, fuel filter, thermostat, anodes

5. Every 2 years, done with every second yearly service

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

   Check: spark plugs, thermostat, anodes

Source: Tohatsu TLDI 115A service manual. Specs can change by model year and serial number, so always confirm your exact model from the serial tag on the clamp bracket.