The Subaru-Robin EX27D is a 265 cc (16.17 cu-in) single-cylinder air-cooled 4-stroke internal combustion small gasoline engine manufactured by Industrial Products division of Subaru Corporation for general-purpose applications.
The Subaru-Robin EX27D engine has an OHС (overhead camshaft) design; high compression ratio for better fuel efficiency; horizontal draft, float type carburetor; recoil starter or electric starter as option and transistorized magneto ignition system.
A 75.0 mm (2.95 in) cylinder bore and 60.0 mm (2.36 in) piston stroke give the motor a total 265 cc (16.17 cu-in) of displacement. Compression ratio rating is 8.3:1. The engine produced 9.0 PS (6.6 kW; 8.9 HP) at 4,000 rpm of maximum horsepower and 6.0 PS (4.4 kW; 5.9 HP) at 3,000 rpm or 6.9 PS (5.1 kW; 6.8 HP) at 3,600 rpm of continuous output power. Maximum torque is 18.6 N·m (1.9 kg·m, 13.7 ft·lb) at 2,500 rpm.
|Type||4-stroke, OHC, single cylinder|
|Displacement||265 cm 3 (16.17 cu-in)|
|Max. horsepower||9.0 PS (6.6 kW; 8.9 HP) at 4,000 rpm|
|Max. torque (crank PTO)||18.6 N·m (1.9 kg·m, 13.7 ft·lb) at 2,500 rpm|
|Carburetor||Horizontal draft, float type carburetor|
|Ignition system||Transistorized magneto ignition|
|Starting system||Recoil or electric starter|
|Stoping system||Ignition primary circuit ground|
|Fuel used||Unleaded gasoline (octane number 86 or higher)|
|Fuel tank capacity||6.1 L (1.61 US. gal. 1.34 Imp. gal.)|
|Fuel consumption||367 g/kWH|
|PTO shaft rotation||Counterclockwise (from PTO shaft side)|
Cylinder Block and Head
The EX27D has cast iron cylinder sleeve, ball bearing supported forged steel crankshaft, improved piston design. The piston has two compression rings and one oil ring.
|Bore x Stroke||75.0 x 60.0 mm (2.95 x 2.36 in)|
|Sleeve internal diameter||75.000-75.019 mm (2.9528-2.9535 in)|
|Piston skirt outer diameter||74.980-75.000 mm (2.952-2.9528 in)|
|Number of piston rings (compression / oil):||2 / 1|
|Ring side clearance||Top||0.035-0.080 mm (0.0014-0.0031 in))|
|Second||0.035-0.080 mm (0.0014-0.0031 in)|
|Oil||0.010-0.065 mm (0.0004-0.0026 in)|
|Ring end gap||Top||0.10-0.30 mm (0.0039-0.0118 in)|
|Second||0.20-0.40 mm (0.0079-0.0157 in)|
|Oil||0.10-0.30 mm (0.0039-0.0118 in)|
|Connecting rod small end ID||18.010-18.020 mm (0.7091-0.7094 in)|
|Connecting rod big end ID||34.500-34.516 mm (1.3583-1.3589 in)|
|Piston pin outer diameter||17.992-18.000 mm (0.7083-0.7087 in)|
|Crankshaft crankpin outer diameter||34.467-34.480 mm (1.357-1.3575 in)|
|Crankshaft main journal diameter||29.998-29.997 mm (1.181-1.181 in)|
|Warpage (limit)||0.10 mm (0.004 in)|
|Stem outer diameter (standard):||INTAKE||5.440-5.455 mm (0.2142-0.2148 in)|
|EXHAUST||5.425-5.445 mm (0.2136-0.2144 in)|
|Valve spring free length:||27.4 mm (1.0787 in)|
|Camshaft lobe height:||INTAKE||29.028-29.128 mm (1.1428-1.1468 in)|
|EXHAUST||29.028-29.128 mm (1.1428-1.1468 in)|
Tightening torque specs
|Tightening torque specs|
|Cylinder head M8 × 68 flange bolt (Re-use)||25-27 Nm; 2.5-2.7 kg·m; 18.1-19.5 ft·lb|
|Cylinder head M8 × 68 flange bolt (New)||28-30 Nm; 2.8-3.0 kg·m; 20.3-21.7 ft·lb|
|Cylinder head M8 × 35 flange bolt||17-19 Nm; 1.7-1.9 kg·m; 12.3-13.7 ft·lb|
|Connecting rod bolt||17-20 Nm; 1.7-2.0 kg·m; 12.3-14.5 ft·lb|
|Main bearing cover bolts||22-24 Nm; 2.2-2.4 kg·m; 16.2-17.7 ft·lb|
|Flywheel nut||59-64 Nm; 5.9-6.4 kg·m; 42.7-46.3 ft·lb|
|Cylinder compression||3.5 kg/cm2|
|Intake valve clearance||0.12-0.15 mm (0.0047-0.0059 in)|
|Exhaust valve clearance||0.12-0.15 mm (0.0047-0.0059 in)|
|Oil type||4-stroke or an equivalent (SE or SF)|
|Recommended oil||SAE 10W-30|
|Oil capacity||1.0 L (1.06 US. qt, 0.88 Imp. qt.)|
|Spark plug gap||0.6-0.7 mm (0.0236-0.0276 in)|
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my engine has been sitting for about 3 to 4 years. it doesn`t start! how do I get it to start??
If fuel was left in it, it is likely the carburetor is clogged up. Google search how to clean a Honda carburetor for info on how to clean it. And stop using gasahol (gasoline/alcohol fuel blend) in it… only burn straight gas. I’d suggest putting in a bit of Marine Stabil in the gasoline as well.
What size is output shaft?