Honda BF15D BF20D Outboard Motors Shop Manual., Page 32Get this manual
Oil Pressure Indicator (Green) Test
1 Stop the engine and inspect the oil 1
levelCorrect level Start the engine and allow it to idleCheck the oil pressure indicator
Low level
Add engine oil to correct level
Indicator ON
4OK, test is complete
Indicator OFF
Disconnect the oil pressure switch wire (yellow) connector and check the indicatorIndicator OFFIndicator ON
1 Check the oil pressure (P2-25)1
Normal Abnormal