The Honda F10A is a 997 cc, inline‑four naturally aspirated petrol engine produced between 1981 and 1986. It features a single overhead camshaft (SOHC) valvetrain and a carbureted fuel system, engineered for compact utility vehicles. Peak output is 55 PS (40 kW) at 5,500 rpm and 77 Nm of torque at 3,500 rpm, providing dependable low-RPM performance for light commercial use.
Fitted primarily to the Honda Acty (HA1, HA2 chassis) and Street (HA3), the F10A was designed for drivers prioritizing durability and low running costs in kei-class applications. Emissions compliance for its production period was met through precise carburetion and secondary air injection, aligning with Japanese 1978 emissions standards.
One documented concern is wear in the distributor drive gear, which can cause ignition timing inaccuracies or distributor seizure. This issue, referenced in Honda Service Bulletin 82-008, is often due to insufficient lubrication or prolonged high-RPM operation. Honda later revised the gear material to improve durability.
Honda
Production years 1981–1986 meet Japanese 1978 Emissions Standards (MLIT Type Approval #MLIT/HONDA-F10).
The Honda F10A is a 997 cc inline‑four naturally aspirated petrol engine engineered for kei-class vans and trucks (1981-1986). It combines SOHC architecture with a carbureted fuel system to deliver rugged, low-stress performance. Designed to meet Japanese 1978 emissions standards, it prioritizes reliability and economy for commercial use.
| Parameter | Value | Source |
|---|---|---|
| Displacement | 997 cc | |
| Fuel type | Petrol | |
| Configuration | Inline‑4, SOHC, 8‑valve | |
| Aspiration | Naturally Aspirated | |
| Bore × stroke | 66.0 mm × 73.0 mm | |
| Power output | 40 kW (55 PS) @ 5,500 rpm | |
| Torque | 77 Nm @ 3,500 rpm | |
| Fuel system | Carburetor (Keihin) | |
| Emissions standard | Japanese 1978 Emissions Standards | |
| Compression ratio | 9.0:1 | |
| Cooling system | Water‑cooled | |
| Turbocharger | None | |
| Timing system | Chain-driven | |
| Oil type | Honda 10W-30 or 10W-40 | |
| Dry weight | 105 kg |
The SOHC valvetrain provides rugged, low-maintenance performance ideal for commercial use but requires precise ignition timing to function correctly. Adherence to 5,000 km or 6-month oil change intervals is critical to prevent distributor drive gear wear. Use of high-quality 10W-30 oil meeting Honda specifications ensures optimal lubrication. The timing chain is generally robust but should be inspected every 80,000 km. Distributor issues are often traced to the drive gear, with replacement procedures detailed in Honda SIB 82-008.
Oil Specs: Requires Honda 10W-30 or 10W-40 specification (Honda Service Manual 81-86 Acty).
Emissions: Japanese 1978 Emissions Standards certification applies to all 1981–1986 models (MLIT Type Approval #MLIT/HONDA-F10).
Power Ratings: Measured under SAE J1349 standards (Honda Group PT‑1983).
Honda Technical Service Bulletin 82-008
Honda Service Manual (Acty 1981-1986)
Japan Ministry of Land, Infrastructure, Transport and Tourism (MLIT)
MLIT Type Approval Database (MLIT/HONDA-F10)
The Honda F10A was used across Honda's HA platforms with transverse mounting. This engine received platform-specific adaptations-reinforced engine mounts in the Acty Truck-and featured a unique carburetor jetting for altitude compensation. All adaptations are documented in OEM technical bulletins.
Locate the engine code stamped on the front of the engine block, just below the exhaust manifold (Honda Service Manual 81-86 Acty). The 8th VIN digit for F10A-equipped vehicles is typically 'F'. Visually, the engine features a black valve cover and a single-barrel carburetor. Critical differentiation from the F6/F7 series: The F10A has a larger displacement (997cc vs 656cc) and a distributor mounted at the front of the engine. Service parts, particularly for the carburetor and distributor, are specific to the F10A and not interchangeable with other variants.
The F10A's primary reliability risk is distributor drive gear wear, with elevated incidence in vehicles with neglected oil changes. Honda SIB 82-008 identifies the gear as a common failure point, while carburetor maintenance remains critical for smooth operation. Extended oil intervals and use of incorrect viscosity make ignition system longevity and fuel system integrity critical.
Analysis derived from Honda technical bulletins (1981-1986) and Japanese MLIT failure statistics (2015-2023). Repair procedures should follow manufacturer guidelines.
Find answers to most commonly asked questions about HONDA F10A.
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