Yamaha F40 (F40B) service guide
Oil, gear oil, spark plugs and the service schedule for the Yamaha F40 (F40B) (40 hp, four-stroke), from the factory service manual, plus how we service it in Hawaiʻi.
Models covered: F40BMH and F40BTR (remote, electric, power trim and tilt) four-strokes, 3 cylinder 747 cm³, carbureted. Model code 67C, starting serial 1035037.
Quick answers
- How much oil does a Yamaha F40 take?
- 2.0 L (2.11 US qt, 1.76 Imp qt) without filter; 2.2 L (2.33 US qt, 1.94 Imp qt) with filter.
- What engine oil does a Yamaha F40 use?
- 4-stroke motor oil, API SE, SF, SG, SH, SJ or SL, SAE 5W-30, 10W-30 or 10W-40 (if not available: API SH, SJ or SL with SAE 15W-40, 20W-40 or 20W-50).
- What gear oil does a Yamaha F40 use, and how much?
- Hypoid gear oil, API GL-4, SAE 90. Quantity: 430 cm³ (14.54 US oz, 15.17 Imp oz).
- What spark plug does a Yamaha F40 use?
- NGK DPR6EA-9, qty 3. Gap: 0.8 to 0.9 mm (0.031 to 0.035 in).
- How often should a Yamaha F40 be serviced?
- The factory schedule lists: Initial 20 hours (3 months); Every 100 hours (1 year); Every 300 hours (3 years); Every 500 hours (5 years); Every 1,000 hours. 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 Yamaha F40?
- The factory schedule says to replace it at 300 hours. In Hawaiʻi's warm salt water we replace it every 200 hours or 1 year, whichever comes first, because a worn impeller is the most common cause of overheating.
- What is the idle speed of a Yamaha F40?
- 850 ± 50 r/min.
- What is the propeller nut torque on a Yamaha F40?
- 39 N·m (3.9 kgf·m, 28.8 ft·lb).
Maintenance specs
| Engine oil | 4-stroke motor oil, API SE, SF, SG, SH, SJ or SL, SAE 5W-30, 10W-30 or 10W-40 (if not available: API SH, SJ or SL with SAE 15W-40, 20W-40 or 20W-50) |
|---|---|
| Engine oil quantity | 2.0 L (2.11 US qt, 1.76 Imp qt) without filter; 2.2 L (2.33 US qt, 1.94 Imp qt) with filter |
| Oil filter | 18 N·m (1.8 kgf·m, 13.3 ft·lb), filter wrench YU-38411; oil the O-ring |
| Engine oil drain bolt | 17 N·m (1.7 kgf·m, 12.5 ft·lb) |
| Gear oil | Hypoid gear oil, API GL-4, SAE 90 |
| Gear oil quantity | 430 cm³ (14.54 US oz, 15.17 Imp oz) |
| Gear oil drain and check screws | 9 N·m (0.9 kgf·m, 6.6 ft·lb), new gaskets |
| Lower unit holding pressure | 100 kPa (1.0 kgf/cm², 14.5 psi), must hold at least 10 seconds; do not over pressurize |
| Spark plug | NGK DPR6EA-9, qty 3 |
| Spark plug gap | 0.8 to 0.9 mm (0.031 to 0.035 in) |
| Spark plug torque | 17 N·m (1.7 kgf·m, 12.5 ft·lb) |
| Idle speed | 850 ± 50 r/min |
| Thermostat | Begins to open (0.05 mm) at 58 to 62 °C (136 to 144 °F); above 70 °C (158 °F) lift more than 3.0 mm (0.12 in) |
| Anodes | Anode bolt (M6) 8 N·m (0.8 kgf·m, 5.9 ft·lb); anode cover bolt (M6) 8 N·m (5.9 ft·lb); trim tab bolt (M8) 18 N·m (1.8 kgf·m, 13.3 ft·lb) |
| Propeller nut | 39 N·m (3.9 kgf·m, 28.8 ft·lb) |
| PTT fluid (F40BTR) | ATF Dexron II; fill to overflow at the filler hole, motor tilted up on the tilt stop lever. Reservoir cap 7 N·m (0.7 kgf·m, 5.2 ft·lb), new O-ring |
| Valve clearance, cold | IN 0.20 ± 0.05 mm (0.008 ± 0.002 in); EX 0.30 ± 0.05 mm (0.012 ± 0.002 in) |
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 20 hours (3 months)
Replace: engine oil, oil drain plug gasket, gear case oil, gear case plug gaskets, propeller cotter pin
Every 100 hours (1 year)
Replace: engine oil, oil filter, oil drain plug gasket, fuel filter, gear case oil, gear case plug gaskets, propeller cotter pin
Check: spark plugs, water pump impeller, thermostat, anodes
Every 200 hours or 1 year (our Hawai‘i yearly service) Hawai‘i
Replace: engine oil, oil filter, oil drain plug gasket, fuel filter, gear case oil, gear case plug gaskets, propeller cotter pin, water pump impeller
Check: spark plugs, thermostat, anodes
Every 300 hours (3 years)
Replace: engine oil, oil filter, oil drain plug gasket, fuel filter, gear case oil, gear case plug gaskets, propeller cotter pin, water pump impeller
Check: spark plugs, thermostat, anodes
Every 500 hours (5 years)
Replace: engine oil, oil filter, oil drain plug gasket, fuel filter, gear case oil, gear case plug gaskets, propeller cotter pin, anodes, water pump impeller
Check: spark plugs, thermostat
Every 1,000 hours
Replace: engine oil, oil filter, oil drain plug gasket, fuel filter, gear case oil, gear case plug gaskets, propeller cotter pin, anodes, water pump impeller
Check: spark plugs, thermostat
We replace the water pump impeller at every service from 200 hours up, which can be sooner than the factory schedule, because of Hawaiʻi’s warm salt water.
Source: Yamaha F40B service manual, LIT-18616-03-04. Specs can change by model year and serial number, so always confirm your exact model from the serial tag on the clamp bracket.