KTM 250 SX, Owner'S Manual

Page: 112 / 145

20 TROUBLESHOOTING
110
Faults Possible cause Action
Engine stalls or is popping into the
carburetor Lack of fuel (All 125/150 models)
–
Turn handle  of the fuel tap to the ON
position. (Figure M01127-10 p. 14)
(250 SX)
–
Turn handle

of the fuel tap to the ON
position. (Figure B02072-10 p. 14)
(All XC models)
–
Turn handle  of the fuel tap to the ON
position. (Figure L00904-10 p. 14)
(All XC models)
–
Turn handle

of the fuel tap to the RES
position. (Figure L00904-10 p. 14)
–
Refuel. ( p. 26)
Engine takes in bad air
–
Check the intake flange and carburetor for
tightness.
The connector or ignition coil is loose
or oxidized
–
Clean the connector and treat it with contact
spray.
Engine overheats Too little coolant in cooling system
–
Check the cooling system for leakage.
–
Check the coolant level. ( p. 94)
Too little air stream
–
Switch off engine when stationary.
Radiator fins very dirty
–
Clean the radiator fins.
Foam formation in cooling system
–
Drain the coolant. ( p. 94)
–
Refill with coolant. ( p. 95)
Damaged cylinder head or cylinder
head gasket
–
Check the cylinder head and cylinder head gas-
ket.
Bent radiator hose
–
Change the radiator hose.
Incorrect ignition point due to loose
stator
–
Adjust the ignition.
White smoke emission (steam in
exhaust gas) Damaged cylinder head or cylinder
head gasket
–
Check the cylinder head and cylinder head gas-
ket.
Gear oil exits at the vent hose Too much gear oil added
–
Check the gear oil level. ( p. 103)
Water in the gear oil Damaged shaft seal ring or water
pump
–
Check the shaft seal ring and water pump.