Onan P218G (18.0 HP, 13.4 kW) Two Cylinders Engine: Specs & Review

Onan P218G Engine Specs

The Onan P218G (Performer 18) is a 47.7 cu-in (782 cc) two-cylinder air-cooled four-stroke internal combustion small gasoline engine with a horizontal shaft made by Onan for general-purpose applications.

The Onan P218G engine has a carburettor fuel system, an electronic battery ignition system, an L-head design with two flat cylinders, an aluminium cylinder block, and an electric starter.

The Onan P218G engine delivered 18.2 PS (13.4 kW; 18.0 HP) at 3,600 rpm horsepower. The Onan P218G engine cylinder bore is 82.55 mm (3.25 in), and the piston stroke is 73.01 mm (2.87 in). The Onan P218G engine compression ratio rating is 7.0:1.

The breakdown of the Onan P218G engine code is as follows:

  • P – Engine Family
  • 2 – Two cylinder
  • 18 – 18.0 BHP power
  • G – Gasoline

Onan P218G Engine Specs

Onan P218G (18.0 HP, 13.4 kW) Two Cylinders Engine Specs

Engine Specifications

Model Onan P218G (Performer 18)
Type 4-stroke, L-head, flat
Displacement 782 cm3 (47.7 cu-in)
Max. horsepower 18.2 PS (13.4 kW; 18.0 HP) at 3,600 rpm
Max. torque
Fuel system Carburettor with the fixed main jet
Cooling system Forced-air
Ignition system Electronic battery ignition system ignition system
Lubricating system Forced lubrication
Starting system Electric starter
PTO shaft rotation Clockwise (viewed from the flywheel)

Cylinder Head

Valve Arrangement: L-haed, gear driven
Valves: 4 (2 per cylinder)
Stem outer diameter (standard): INTAKE 7.099-7.112 mm (0.2795-0.2800 in)
EXHAUST 7.061-7.074 mm (0.2780-0.2785 in)
Valve spring free length: 40.640 mm (1.6 in)
Lobe height: INTAKE 28.880 mm (1.1370 in)
EXHAUST 29.390 mm (1.1571 in)

Cylinder block

Compression ratio: 7.0:1
Bore x Stroke 82.55 X 73.00 mm (3.25 x 2.87 in)
Sleeve internal diameter 82.530-82.550 mm (3.2492-3.25 in)
Piston skirt’s outer diameter 82.420-82.440 mm (3.2449-3.2457 in)
Ring end gap Top/Second 0.076-0.203 mm (0.003-0.008 in)
Connecting rod small end ID 17.470-17.480 mm (0.6878-0.6882 in)
Piston pin outer diameter 17.463-17.468 mm (0.6875-0.6877 in)
Crankpin diameter 41.280-41.300 mm (1.6252-1.626 in)
Crankshaft main journal diameter 50.780-50.800 mm (1.9992-2 in)

Service Information

Maximum speed 3,600
Cylinder compression 517-793 kPa (75 to 115 psi)
Valve clearance
Intake valve clearance 0.130 mm (0.0051 in)
Exhaust valve clearance 0.330 mm (0.0130 in)
Oil system
Oil type: API SF, SF/CC, or SF/CD
Recommended oil: SAE 5W-30, 10W-30, 30W, 40W
Oil Capacity Without oil filter:
Standard base: 1.4 L (1.5 US. qt, 1.2 Imp. qt.)
High capacity base: 2.6 L (2.75 US. qt, 2.3 Imp. qt.)
Oil filter: 0.3 L (0.32 US. qt, 0.26 Imp. qt.)
Ignition system
Ignition timing 20° B.T.D.C.
Spark plug NGK BPR5EFS, Champion RS14YC
Spark plug gap 0.640 mm (0.0252 in)

Also Check:

Final Words

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