Onan MJA Series Service Manual page 67

65 OIL SYSTEM
TROUBLE-SHOOTING CHART 6, OIL SYSTEM (Cont.)
TROUBLE POSSIBLE CAUSE RElVlEDY
Low oil pressure Defective oil gauge Replace gauge
(Cont. )
High oil pressure
Oil by-pass stuck closed Clean
Oil too heavy
Replace with lighter
oil
Clogged oil passages
Clean all lines and
oil passages