diode and lead assembly - what is it?

[JT!]

(1971 evinrude 50 selectric)​

i have just replaced my rectifier with a brandnew one. (the used one was defective and returned)​

now before firing everything up, i think i should test my diode & lead assembly. the manual doesnt seem to cover this item at all -or- i missed it.​

how does it work? it appears to be connected to the selectric shift.
how do i test it? i understand diodes, but whats the test sequence?

thanks​

 

[larky]

Re: diode and lead assembly - what is it?

PAGE 8-5 OF YOUR MANUAL (if the same as mine)

SHIFT DIODES:
1. Disconnect shift diodes from terminal board (key switch off)
2. connect one ohmmeter test probe to shift diode purple?green lead. connect other ohmmeter probe to yellow lead.
3. use high ohm scale - note reading.
4. reverse test probes - note reading.
5. one high and one zero reading - diode ok.
6. repeat test using yellow/gray lead and purple/green leads.
7. both high readings on one test - diode open.
8. both zero readings on one test - diode shorted.

 

[Vic.S]

Re: diode and lead assembly - what is it?

If your meter has "diode test" range use that rather than an ohms range.

 

[JT!]

Re: diode and lead assembly - what is it?

perfect, thanks.

now can anyone tell me why that diode assembly is there? how come it operates in parallel to the rectifier? if it's a powersource for the shifter, how come it doesnt get sourced from the regulator?

JT​

 

[F_R]

Re: diode and lead assembly - what is it?

Think about it: The default for the selectric shift is forward gear. That is, it takes a voltage from the shift switch to make it go into neutral.

So, when you turn the key off, there is no voltage to the shift switch and therfor no voltage to hold it in neutral. So what happens? The instant you turn the key off, the motor goes into forward gear. Not a real big deal but a bit agrevating.

Enter the shift diodes: The shift diodes provide an alternate power source for the shift....the alternator. As long as the alternator is spinning, the shift receives a voltage to keep it in neutral. When the alternator stops spinning, it quietly slips into forward gear almost unnoticed.

You will also find a blocking diode in the feed from the ignition switch to the shift switch. If it were not for the blocking diode, the shift diodes would feed the ignition circuit after the key is turned off and you wouldn't be able to kill the motor.

 

[JT!]

Re: diode and lead assembly - what is it?

thank you sir.​