Onan CCKA User Manual

Oil System
PRESSURE LUBRICATION
These engines use an oil pump to lubricate engine
parts (Figure 8). If oil pressure is low, the pump
should be checked.
FIGURE 8. OIL SYSTEM
OIL PUMP
The oil pump (Figure 9) is mounted on the front of the
crankcase behind the gear cover and is driven by the
crankshaft gear.
A drilled passage connects the front main bearing oil
supply to the front camshaft bearing. The flyball
governor is lubricated by a drilled passage in the front
camshaft journal.
The oil overflow from the bypass valve furnishes
iubncation to the camshaft drive gears.
Norma! oil pressure should be 30 psi or higher when
the engine is at operating normal temperature. If
pressure drops below 30 psi at governed speed,
inspect the oil system for faulty components.
Check the oil pump thoroughly for worn parts. Oil the
pump to prime it before reinstalling. Except for
gaskets and suction cup, the component parts of the
pump are not available individually. Install a new
pump assembly if required.
It new oil pump gaskets are installed, they should be
the same thickness as those removed. A gasket kit
with various thickness gaskets is available.
OIL BY-PASS VALVE
The by-pass valve (located to the right and behind
gear cover, Figure 10), controls oil pressure by
allowing excess oil to flow directly back to the
crankcase. Normally the valve begins to open about
30 psi.
The valve is non-adjustable and normally needs no
maintenance. To determine if abnormal (high or low)
oil pressure is caused by a sticky plunger inspect as
follows:
1. Remove 3/8" - 24 x 3/4 inch cap screw located
behind gear cover and under governor arm.
Z Remove spring and plunger with a magnet tool.
Clean plunger and spring with a suitable solvent
and reinstall.
FIGURE a OIL PUMP ASSEMBLY
The inlet pipe and screen assembly is attached
directly to the pump body. A discharge passage in the
cover of the pump registers with a drilled passage in
the crankcase. Parallel passages distribute oil to the
front main bearing, rear main bearing and pressure
control bypass valve.
Circumferential grooves in the main bearings supply
oil to the connecting rod bearings through drilled
passages from each main journal.
Removal
To remove the valve, unscrew the recessed plug in the
rear bearing plate and lift out the spring and plunger
assembly. Determine proper valve operation by
checking the spring and plunger according to the
following measurements.
Plunger Diameter.3365" to .3380"
(8.55 to 8.59 mm)
Spring
Free Length. 2-5/16” (58.74 mm)
2.225 (1.0 kg) .11 lb. (49.9g) at 1-3/16" (30.16 mm)
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Onan CCKA Specifications

General

Cylinders	2
Ignition System	Battery ignition
Engine Type	4-cycle
Bore	3.25 in (82.55 mm)
Power Output	Varies with model. e.g., 6.5 kW (CCK)
Horsepower	10 hp
Starter	Electric