ONL843NW4 11/13
15
SP4. AIR CLEANER
1. Inspect air cleaner every 250 hours. In dusty
conditions, check more often.
2. Replace if necessary. Part number is:
NL843NW3
(
element
only
)
– #24-27302
3.
NOTE:
Make absolutely sure no impurities enter
the engine while changing the element. Do NOT
run the engine with the air cleaner removed.
SP5. V-BELTS
1. Check the tension and wear on the V-belt daily.
2. Use your thumb to press on the belt at the midpoint
between the crankshaft and alternator pulleys. The
tension is correct if the belt can be depressed about
3/16 in. (5 mm). Fan belt slackness should be about
3/16 in. (5 mm).
3. To adjust the belt tension loosen the alternator
adjusting plate bolt and the alternator mounting bolt.
Pivot the alternator at the mounting bolt as needed.
4. Tighten the mounting bolt and the adjusting bolt.
5. Operate engine at low idle speed and recheck the
belt tension.
Servicing
Figure 6:
Valve Adjustment
SP6. VALVE CLEARANCES
1. Adjust valve clearance after the first and then at
1000 hours, or as needed.
2. Engine should be cold and NOT running.
3. Watch the valves while turning the engine over by
hand. Turn until the inlet valve starts to open and the
exhaust valve starts to close (the valves are
rocking). Then turn the crankshaft one more full
turn and adjust the clearance on both valves for this
cylinder. Align the top mark of the crank pulley with
the TOP mark of the timing gear case.
4. Loosen the lock nut and adjust the clearance between
the rocker arm and valve guide of both the intake
and exhaust valves with the adjustment screw (
Figure
6
). Clearance on both intake and exhaust valves
should be 0.008 in. (0.2 mm).
5. Repeat steps 3 and 4 for each cylinder. Each set of
valves must be adjusted individually.
6. Replace the rocker arm cover. Tighten cover nuts to
5 - 8 ft/lbs (0.8 - 2.3 kg/m).
Figure 7:
843
NW3
Valve sequence
In Ex In Ex In Ex
No. 1 No. 2 No. 3
Cylinder
Valve
Arrangement
When No. 1
cyl. is at TDC
in compression
stroke
With the
crankshaft
turned by 360
0
in normal
direction from
above
Figure 5:
Timing mark
