Honda BF2 / BF2A (2 hp, air cooled) service guide
Oil, gear oil, spark plugs and the service schedule for the Honda BF2 / BF2A (2 hp, air cooled) (2 hp, four-stroke), from the factory service manual, plus how we service it in Hawaiʻi.
Models covered: Honda BF20S, BF20L, BF2AS and BF2AL; 4-stroke, side valve, 1 cylinder, 76 cm³ (4.6 cu in), bore and stroke 46 x 46 mm, 2.0 HP at 5,000 rpm at the propeller shaft, forced-air cooling with water cooling for the exhaust system only, transistorized magneto, splash-type lubrication, recoil starter, 1.0 L built-in fuel tank, gear ratio 13 : 28.
Quick answers
- How much oil does a Honda BF2 / BF2A take?
- 0.4 L (0.42 US qt) to the upper level mark; the lower level mark is 0.2 L (0.21 US qt). Check with the dipstick resting on the filler opening, not screwed in. There is no oil filter.
- What engine oil does a Honda BF2 / BF2A use?
- SAE 10W-40 recommended for general, all-temperature use; API SE or SF.
- What gear oil does a Honda BF2 / BF2A use, and how much?
- SAE 90 outboard motor gear oil, API GL-4 or GL-5. Quantity: 0.05 L (0.053 US qt); inject through the drain bolt hole until it flows out of the level bolt hole.
- What spark plug does a Honda BF2 / BF2A use?
- BF20: NGK BMR-4A. BF2A: NGK BMR-4A or ND W14MR-U. Qty 1. Gap: 0.6 to 0.7 mm (0.024 to 0.028 in).
- How often should a Honda BF2 / BF2A be serviced?
- The factory schedule lists: First month or 20 hours; Every 6 months or 100 hours; Every year or 200 hours; Every 300 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.
- What is the propeller nut torque on a Honda BF2 / BF2A?
- Held by a shear pin and a 3 mm cotter pin (no propeller nut). Use a genuine Honda stainless pin; replace the shear pin when badly corroded. 3 blades, 184 x 120 mm (7.2 x 4.7 in).
Maintenance specs
| Engine oil | SAE 10W-40 recommended for general, all-temperature use; API SE or SF |
|---|---|
| Engine oil quantity | 0.4 L (0.42 US qt) to the upper level mark; the lower level mark is 0.2 L (0.21 US qt). Check with the dipstick resting on the filler opening, not screwed in. There is no oil filter |
| Gear oil | SAE 90 outboard motor gear oil, API GL-4 or GL-5 |
| Gear oil quantity | 0.05 L (0.053 US qt); inject through the drain bolt hole until it flows out of the level bolt hole |
| Gear oil drain and level bolts | Tighten "securely" |
| Spark plug | BF20: NGK BMR-4A. BF2A: NGK BMR-4A or ND W14MR-U. Qty 1 |
| Spark plug gap | 0.6 to 0.7 mm (0.024 to 0.028 in) |
| Fuel filter | A filter on the fuel tank outlet, inside the built-in tank; Tube clip about 5 mm from the tube end |
| Propeller | Held by a shear pin and a 3 mm cotter pin (no propeller nut). Use a genuine Honda stainless pin; replace the shear pin when badly corroded. 3 blades, 184 x 120 mm (7.2 x 4.7 in) |
| Valve clearance, cold | IN and EX 0.08 to 0.16 mm (0.003 to 0.006 in), piston at TDC on the compression stroke. Not adjustable by a screw: corrected by fitting a replacement valve adjuster or lapping the adjuster |
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 month or 20 hours
Replace: engine oil, oil drain plug gasket, gear case oil, gear case plug gaskets
Every 6 months or 100 hours
Replace: engine oil, oil drain plug gasket, gear case plug gaskets
Check: spark plugs, gear case oil
Every year or 200 hours
Replace: engine oil, oil drain plug gasket, gear case oil, gear case plug gaskets
Check: spark plugs
Every 300 hours
Replace: engine oil, oil drain plug gasket, gear case plug gaskets
Check: spark plugs, gear case oil
Source: Honda BF20·BF2A Shop Manual, part no. 66ZV001. Specs can change by model year and serial number, so always confirm your exact model from the serial tag on the clamp bracket.