Honda BF35A-BF45A Outboard Motors Shop Manual., Page 290Get this manual
cALERT SYSTEM Long Tiller Handle Type:
No problem if the oil pressure light comes OFF when the engine speed is slowed down suddenly, but goes ON after idling for or minutes
1Stop the engine and check the oil levelIs the oil level correct?
LOW LEVEL
Fill to the proper level and recheck
CORRECT LEVEL
2Start the engine and check the oil pressure light with the engine idlingDoes the oil pressure light comes ON?
System is OK (oil level was low)
3Disconnect the oil pressure switch