Rectifier check?

[Ddono29485]

I checked the the rectifier on a 1987 25 HP XD and followed the checkout instructions in a manual for 6 to 15 hp engines that I found....don't have a service manual for this one........the rectifier checked out using an ohm meter except the resistance levels were all significantly higher than that manual said to use.......how do you know for sure it's working?

 

[Chris1956]

Rectifiers on outboards are a set of four diodes. Each diode is a one way valve for electricity. If you check the rectifier correctly the analog ohm meter should read either zero ohms resistance or infinite resistance. So if you check a diode with the ohmmeter and it reads zero resistance, reverse the ohmmeter leads and it should read infinite resistance. ​Some digital ohmmeters work differently.

 

[sam am I]

how do you know for sure it's working?

For sure for sure? Follow what Chris suggested, then put it in circuit.........Make it do some work!!

Use your volt meter, rev the engine up to around 1500RPM's and check the batt voltage. 14-15VDC says it's working for sure......

 

[gm280]

Some DVMs have a diode check built into them and will show around a 0.6XX +/- voltage drop across the diode in a forward bias direction showing that it is in good working order. And not all meter will show a ZERO ohms resistance for the forward resistance. Some meter will show a low reading one direction and an extremely high resistance when you reserve the lead orientation. So when you measure a diode, it will allow more voltage to pass through one direction then the other direction. But it drops (takes away) a small portion of the voltage when doing that. JMHO