What two-stroke oil does a Tohatsu M90A and M80A use?

Tohatsu Genuine 2-cycle Engine Oil Gold.

What is the fuel to oil ratio for a Tohatsu M90A and M80A?

Auto mixing model: 50:1 to 120:1, set by the oil pump. Hand mixing model: 50:1 after break-in running. A new auto mixing motor also gets a 50:1 mix in the fuel tank aside from the oil in the oil tank.

What gear oil does a Tohatsu M90A and M80A use, and how much?

Tohatsu Genuine gear oil. Quantity: Approx. 30 US fl oz (900 mL) for the 80 / 90. Fill until it shows at the level plug.

What spark plug does a Tohatsu M90A and M80A use?

NGK B8HS-10 or Champion L78C, qty 3. Gap: 0.9 to 1.0 mm.

How often should a Tohatsu M90A and M80A be serviced?

The factory schedule lists: Initial 10 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 M90A and M80A?

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 M90A and M80A?

Trolling 550 to 750 rpm; idling adjustment after synchronizing the 3 carburetors: pilot screw 1 1/2 ± 1/4 turns out, 550 to 700 rpm with the clutch at F.

Tohatsu M90A and M80A (3 cylinder, 1,267 cc, carbureted two-stroke) service guide

Oil, gear oil, spark plugs and the service schedule for the Tohatsu M90A and M80A (3 cylinder, 1,267 cc, carbureted two-stroke) (80 to 90 hp, two-stroke), from the factory service manual, plus how we service it in Hawaiʻi.

Models covered: M90A, model 3B7, in the EPTO, EPT, EFT and EF versions. 3 cylinders, 1,267 cc, bore 86 x stroke 72.7 mm, 3 carburetors, reed valves; 90 PS, full speed range 5,000 to 5,500 rpm; gear ratio 13:26. Auto mixing with an integral oil tank of about 3.5 liters; a hand mixing version is also listed.

Quick answers

What two-stroke oil does a Tohatsu M90A and M80A use?: Tohatsu Genuine 2-cycle Engine Oil Gold.
What is the fuel to oil ratio for a Tohatsu M90A and M80A?: Auto mixing model: 50:1 to 120:1, set by the oil pump. Hand mixing model: 50:1 after break-in running. A new auto mixing motor also gets a 50:1 mix in the fuel tank aside from the oil in the oil tank.
What gear oil does a Tohatsu M90A and M80A use, and how much?: Tohatsu Genuine gear oil. Quantity: Approx. 30 US fl oz (900 mL) for the 80 / 90. Fill until it shows at the level plug.
What spark plug does a Tohatsu M90A and M80A use?: NGK B8HS-10 or Champion L78C, qty 3. Gap: 0.9 to 1.0 mm.
How often should a Tohatsu M90A and M80A be serviced?: The factory schedule lists: Initial 10 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 M90A and M80A?: 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 M90A and M80A?: Trolling 550 to 750 rpm; idling adjustment after synchronizing the 3 carburetors: pilot screw 1 1/2 ± 1/4 turns out, 550 to 700 rpm with the clutch at F.
What is the propeller nut torque on a Tohatsu M90A and M80A?: 3.0 to 4.0 kg-m.

Maintenance specs

Injection (two-stroke) oil	Tohatsu Genuine 2-cycle Engine Oil Gold
Fuel to oil ratio	Auto mixing model: 50:1 to 120:1, set by the oil pump. Hand mixing model: 50:1 after break-in running. A new auto mixing motor also gets a 50:1 mix in the fuel tank aside from the oil in the oil tank
Oil tank	Integral tank, approx. 3.5 L, with oil level sensor, warning lamp and buzzer
Gear oil	Tohatsu Genuine gear oil
Gear oil quantity	Approx. 30 US fl oz (900 mL) for the 80 / 90. Fill until it shows at the level plug
Spark plug	NGK B8HS-10 or Champion L78C, qty 3.
Spark plug gap	0.9 to 1.0 mm
Spark plug torque	2.5 to 3.0 kg-m (18.07 to 21.68 lb-ft)
Trolling / idle speed	Trolling 550 to 750 rpm; idling adjustment after synchronizing the 3 carburetors: pilot screw 1 1/2 ± 1/4 turns out, 550 to 700 rpm with the clutch at F.
Thermostat	Wax type with pressure relief valve: starts to open at 60 °C, fully open at 70 °C or greater
Anodes	Trim tab, cylinder head and power trim and tilt: inspect each time used, replace if wear is approximately 1/3; remark "Each year"
Propeller nut	3.0 to 4.0 kg-m
Power trim and tilt fluid	ATF oil, for example Shell Dexron-II, Esso ATF, Mobil DTE #22. Tilt up, set the tilt stopper, remove the oil plug and check the oil is just below the oil plug hole

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.

Initial 10 hours or 1 month

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

Check: spark plugs, fuel filter
Every 50 hours or 3 months

Replace: gear case plug gaskets, propeller cotter pin

Check: spark plugs, fuel filter, gear case oil
Every 100 hours or 6 months

Replace: gear case plug gaskets, propeller cotter pin

Check: spark plugs, fuel filter, gear case oil, water pump impeller, thermostat
Every 200 hours or 1 year

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

Check: spark plugs, fuel filter, thermostat, anodes

Source: Tohatsu M90A 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.

Tohatsu M90A and M80A (3 cylinder, 1,267 cc, carbureted two-stroke) service guide

Quick answers

Maintenance specs

Service schedule

Initial 10 hours or 1 month

Every 50 hours or 3 months

Every 100 hours or 6 months

Every 200 hours or 1 year

Other Tohatsu guides