1974 Johnson 40 HP Outboard Motors Service manual, Page 81Get this manual
Set Ohmmeter Scale to Hi Ohms Connect the ohmmeter's ed lead to groundSee Figure 7- 18Ohmmeter should show open circuit (infinity) If ohmmeter shows any eading, stator is shorting to ground OHMMETER LEADS MUST BE REVERSED FOR EACH TEST OR PRESS POLARITY BUTTON
a Repeat above tes using yellow rectifier leadReading on one check and no reading (infinity) on the other checkdiode is good; both readings high, diode is (open) defeCtive; both readings zero, diode is (shorted) defectivebRepeat above test usin yellow blue stripe leadReadi ng on one check and no reading (inIinity) on the other checkdiode is good; both readings high, diode is (open) defective; both readings zero, diode is (shorted) defective2Repeat test procedure wi th ohmmeter between red lead of rectifier and yellow gray tripe lead of rectifier"Reading on one check and no reading (infinity) on the other checkdiode is good; both readings hi gh, diode is (open) detective; both readings zero, diode is (shorted) defectivea Repeat test between red and yellow lead of rectifierReading on one check and no reading (in finity) on the other checkdiode is good; both readings high, diode is (open) defective; both readings zero, diode is (shorted) defective