Komatsu F30791, Shop Manual

Page: 141 / 298

CHECKING THE ENGINE SPEED
20-25
TESTING AND ADJUSTMENTS CHECKING THE ENGINE SPEED
When checking the engine rpm , always be very
careful not to touch parts that reach high tempera-
tures and not to get entangled in rotating elements.
H Check the engine speed after the following conditions
have been reached:
.
Temperature of engine cooling water: 68 ± 80 ëC.
. Temperature of hydraulic oil: 45 ± 55 ëC.
1 - Mount and connect the tachometer C1 .
H If the stroboscopic tachometer C2 is used, make a
distinct mark on the engine pulley to facilitate the
reading.
2 - Start the engine and check:
.
Low idling without load (accelerator lever in "mini-
mum" position).
.
High idling without load (accelerator lever in
"maximum" position).
H Low idling:
PC20R-8: 950 w 25 rpm
PC27R-8: 1050 w 25 rpm
H High idling:
PC20R-8: 2780 w 25 rpm
PC27R-8: 2785 w 25 rpm
H If the minimum and maximum speeds do not fall
within permissible limits when the engine is with-
out load, check the position locks of the accelera-
tor lever, and the sheathing of the accelerator
well, before carrying out any tests under load.
(See «ADJUSTMENT OF THE ACCELERATOR
LEVER»).
. Engine rpm with the pumps under load.
H Boom at max. pressure:
PC20R-8: 2740 w 50 rpm
PC27R-8: 2650 w 50 rpm
H Boom and swing at max. pressure:
PC20R-8: 2720 w 50 rpm
PC27R-8: 2625 w 50 rpm
H If engine efficiency does not fall within permissi-
ble limits, have the engine checked by an
authorised workshop.
PC20R-8 PC27R-8
RKPA2230
C
1
RKPB5490
MAX
MIN