Suzuki DF 2.5 Service Manual page 95

OIL SEAL AND BEARING
Visually check the oil seals installed in the cylinder block and
crankcase for cut, nick, excessive wear or other damage.
Visually check the crankshaft upper bearing for pitting, noisy,
rough or other damage.
NOTE:
If neither defective nor any damage is found on the oil seals and
the bearing, do not remove the oil seals and the bearing.

Do not re-use the oil seal once removed. Always use a
new oil seal.
Drive the oil seal down into the position as shown in the figure.
A: Crankshaft upper oil seal
B: Crankshaft lower oil seal
C: Driveshaft oil seal
POWER UNIT 6-29
A
Crankcase inside
C
Crankcase inside