Yamaha LB50IIAC - Page 71

4. Troubleshooting and repair
a. Wear or an internal malfunction may
cause
pump output to vary from the
factory setting. This situation is,
however, extremely rare. If output is
suspect. check the following:
1) Obstructions in delivery line to pump
or from pump to cylinder.
2) Worn or damaged pump body seal
or crankcase cover seal.
3) Missing or improperly installed
check ball or spring.
4) Improperly installed or routed oil
delivery line(s).
Autolube Pump Specifications
LB50 II AC:
Maximum Throttle
Min ..
Max ........... .
Minimum Throttle
Min.
Max ....
LB801IAC:
Maximum Throttle
Min.
Max ................. .
Minimum Throttle
Min.
Max.
5. Reassembly
0.55
mm
0.65 mm
0.20 mm
0.25 mm
0.80 mm
0.95 mm
0.25 mm
0.30 mm
Always install a new pump case gasket.
-66-
5) Loose fitting(s) allowing air entry to
pump and/or engine.
b. If all inspections show no obvious
problems and output is still suspect.
connect the delivery line from the pump
to a graduated container (cc). Keep the
delivery line short. Remove spark plug.
Open
throttle to full open position.
Operate kick
starter continuously and
count the oil pump plunger strokes. If
output is not to specification. replace
pump assembly.