Onan P224G

Onan P224GThe Onan P224G (Performer 24) is a 983 cc (60.0 cu-in) two-cylinder air-cooled four-stroke internal combustion small gasoline engine with a horizontal shaft manufactured by Onan for general-purpose applications.

The P224G engine has an L-head design with two flat cylinders, an aluminum cylinder block, a carburetor fuel system, an electronic battery ignition system, and an electric starter.

The cylinder bore is 90.4 mm (3.56 in) and the piston stroke is 76.2 mm (3.00 in), the compression ratio rating is 7.0:1. The Onan P224G engine produced 24.3 PS (17.9 kW; 24.0 HP) at 3,600 rpm of horsepower.

The breakdown of the engine code is as follows:

  • P – Engine Family
  • 2 – Two cylinder
  • 24 – 24.0 BHP power
  • G – Gasoline

General information

Engine Specifications
Model Onan P224G (Performer 24)
Type 4-stroke, L-head, flat
Displacement 983 cm3 (60.0 cu-in)
Max. horsepower 24.3 PS (17.9 kW; 24.0 HP) at 3,600 rpm
Max. torque
Fuel system Carburetor with 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 flywheel)

Cylinder Block and Head

Cylinder block
Compression ratio: 7.0:1
Bore x Stroke 90.4 X 76.2 mm (3.56 x 3.00 in)
Sleeve internal diameter 90.510-90.490 mm (3.5634-3.5626 in)
Ring end gap Top/Second 0.254-0.508 mm (0.01-0.02 in)
Connecting rod small end ID 19.060-19.070 mm (0.7504-0.7508 in)
Piston pin outer diameter 19.060-19.070 mm (0.7504-0.7508 in)
Crankpin diameter 44.460-44.480 mm (1.7504-1.7512 in)
Crankshaft main journal diameter 50.780-50.800 mm (1.9992-2 in)
Cylinder Head
Valve Arrangement: L-haed, gear driven
Valves: 4 (2 per cylinder)
Stem outer diameter (standard): INTAKE 8.700-8.712 mm (0.3425-0.343 in)
EXHAUST 8.661-8.687 mm (0.341-0.342 in)
Valve spring free length: 42.21 mm (1.6618 in)
Lobe height: INTAKE 29.640 mm (1.1669 in)
EXHAUST 29.390 mm (1.1571 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)
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We try to use verified sources and official documentation, however, differences between sources or errors in entering information may occur. We do not provide advice on technical issues related to the engines operation or repair. We do not recommend using provided information for engines repairing engines or spare parts ordering, use only official service manuals and spare-parts catalogs.


  1. I have a P224G engine on my LT40HD sawmill. I am having problems with the engine and think the right piston wrist pin has come loose or wallered out. either way I am looking at a rebuild or replacing the engine. Do you have a rebuilt engine or have rebuild kits or do rebuilds. I’ll need gaskets seals and at least one piston maybe the rod as well. The model number is P224G-I7084. Thank you!

    • I don’t think these folks sell parts.
      The old onan p224 parts are getting impossible to find. It’s worth the money to just repower.
      I’ve seen good things with the harbor freights predator 670. It cost around $1000. Vs. the Honda gx690 @ $3500. Which is the recommended replacement engine.

  2. I have one in good condition from a huge 2 boiler pressure washer. The washer is an early 90’s model and the engine is a 2001 Linamar/Onan Performer 24 with 900hrs. I’m in Central PA. I would probably sell it for $500. It has the high-capacity base, which (as it shows above) allows it to hold 3 quarts of oil. It also has a bolt-on extra bearing plate which keeps you from ruining the crank bearings if you have high belt tension. The pulley is a 3 belt setup, 1 belt ran a small generator head and the other 2 belts ran a 6 piston (double ended) pressure washer head.

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