Tohatsu MD30B2 / MD40B2 / MD50B2 TLDI (3 cylinder, 697 cc, direct injection two-stroke) service guide
Oil, gear oil, spark plugs and the service schedule for the Tohatsu MD30B2 / MD40B2 / MD50B2 TLDI (3 cylinder, 697 cc, direct injection two-stroke) (30 to 50 hp, two-stroke), from the factory service manual, plus how we service it in Hawaiʻi.
Models covered: TLDI D30B2 (22.1 kW, 30 ps), D40B2 (29.4 kW, 40 ps) and D50B2 (36.8 kW, 50 ps), plus the D40B2Z and the WD50B2, in EPTO, EFTO, EFO and EPOL versions. 2-stroke gasoline direct injection (TLDI), 3 cylinders, 697 cm3 (42.5 cu in), bore 68 x stroke 64 mm, W.O.T. 5,150 to 5,850 r/min, oil injection, ECU, inductive ignition; gear ratio 1:1.85 (13:24), WD50B2 1:1.917 (12:23).
Quick answers
- What two-stroke oil does a Tohatsu MD30B2 / MD40B2 / MD50B2 TLDI use?
- Genuine oil: oil for two stroke direct injection engines recommended by the outboard manufacturer.
- What gear oil does a Tohatsu MD30B2 / MD40B2 / MD50B2 TLDI use, and how much?
- Genuine gear oil or hypoid gear oil, API GL-5, SAE #80 to #90. Quantity: D30 / D40 / D50B2: 500 cm3 (16.91 fl oz). WD50B2: 700 cm3 (23.67 fl oz).
- What spark plug does a Tohatsu MD30B2 / MD40B2 / MD50B2 TLDI use?
- NGK IZFR6Q in the maintenance data and the inspection procedure; Qty 3. 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 MD30B2 / MD40B2 / MD50B2 TLDI be serviced?
- The factory schedule lists: First 20 hours or 1 month; Every 50 hours or 3 months; Every 100 hours or 6 months; Every 200 hours or 1 year. 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 MD30B2 / MD40B2 / MD50B2 TLDI?
- The factory schedule says to replace it at 200 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 MD30B2 / MD40B2 / MD50B2 TLDI?
- 700 / 800 / 900 r/min (3 stages variable), in neutral and in forward.
- What is the propeller nut torque on a Tohatsu MD30B2 / MD40B2 / MD50B2 TLDI?
- 35 N·m (25 lb-ft, 3.5 kgf·m), M16 x 1.5.
Maintenance specs
| Injection (two-stroke) oil | Genuine oil: oil for two stroke direct injection engines recommended by the outboard manufacturer |
|---|---|
| Oil tank | 2.0 L (0.53 US gal) |
| Gear oil | Genuine gear oil or hypoid gear oil, API GL-5, SAE #80 to #90 |
| Gear oil quantity | D30 / D40 / D50B2: 500 cm3 (16.91 fl oz). WD50B2: 700 cm3 (23.67 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 without air bubbles; 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) at the upper oil plug hole, must hold 10 seconds; do not exceed it |
| Spark plug | NGK IZFR6Q in the maintenance data and the inspection procedure; Qty 3 |
| 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); hand-tighten fully first |
| Idle / trolling speed | 700 / 800 / 900 r/min (3 stages variable), in neutral and in forward |
| Thermostat | Valve opening temperature 52 °C (125.6 °F); valve lift 3 mm (0.12 in) or more at 65 °C (149 °F) or more; with pressure relief valve |
| Fuel filters | Fuel filter with cup (red float shows water): clean the cup, replace the filter if necessary. High pressure fuel filter: a disposable cartridge, replace every 200 hrs or 2 years. Air compressor air filter: replace when the paper turns brownish (clogged) |
| Propeller nut | 35 N·m (25 lb-ft, 3.5 kgf·m), M16 x 1.5 |
| Power trim and tilt fluid | ATF Dexron III, 325 cm3 (10.98 fl oz); reservoir cap 1.8 N·m |
| Air compressor drive belt | Tension 30 to 230 N (Unitta tension gauge); check tension and appearance. Driven pulley nut 47 N·m, drive pulley nut 100 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.
First 20 hours or 1 month
Replace: gear case oil, gear case plug gaskets, propeller cotter pin
Check: spark plugs
Every 50 hours or 3 months
Replace: gear case plug gaskets, propeller cotter pin
Check: fuel filter, water pump impeller, anodes
Every 100 hours or 6 months
Replace: gear case oil, gear case plug gaskets, propeller cotter pin
Check: spark plugs, fuel filter, water pump impeller, thermostat, anodes
Every 200 hours or 1 year
Replace: fuel filter, gear case oil, gear case plug gaskets, propeller cotter pin, water pump impeller
Check: spark plugs, thermostat, anodes
Source: Tohatsu TLDI D30/40/50B2 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.