841 Solenoid Operation

JWA

Member

Help me understand the operation of the starter solenoid on my 841. It is my understanding that when the transmission mounted starter switch is depressed its function is to ground the actuation coil in the solenoid switch and completing the circuit to send power to the starter motor and turning the engine over to start. Is this correct? Also should there normally be continuity between the S start terminal and the mounting bracket?
I ask these questions because my solenoid failed and I have ordered a replacement from three different sources including this site after calling them and being assured that the one I was ordering was correct. All three of the ones that I have received have continuity between the S terminal and the base. The description of the one I ordered from this site specifically states that it does not ground through the base yet the is continuity.
I have owned this tractor for twelve years and operated flawlessly until the solenoid started going bad about a year back and a tap with a hammer would make it work until it finally gave up the ghost, wired by JMOR's wiring schematic with a 3 wire alternator, I have checked that the starter switch and wire to the solenoid are funtioning correctly. Any help, am I wrong in my understanding of the solenoid operation, anybody got a good part number and supplier for the correct solenoid.Thanks Bill
 

I had a very similar experience with my 841. The nearby starter shop found one with the correct configuration in their book. No idea what the Ford part number is (yet).
 
(quoted from post at 15:15:09 03/18/22)
Help me understand the operation of the starter solenoid on my 841. It is my understanding that when the transmission mounted starter switch is depressed its function is to ground the actuation coil in the solenoid switch and completing the circuit to send power to the starter motor and turning the engine over to start. Is this correct? Also should there normally be continuity between the S start terminal and the mounting bracket?
I ask these questions because my solenoid failed and I have ordered a replacement from three different sources including this site after calling them and being assured that the one I was ordering was correct. All three of the ones that I have received have continuity between the S terminal and the base. The description of the one I ordered from this site specifically states that it does not ground through the base yet the is continuity.
I have owned this tractor for twelve years and operated flawlessly until the solenoid started going bad about a year back and a tap with a hammer would make it work until it finally gave up the ghost, wired by JMOR's wiring schematic with a 3 wire alternator, I have checked that the starter switch and wire to the solenoid are funtioning correctly. Any help, am I wrong in my understanding of the solenoid operation, anybody got a good part number and supplier for the correct solenoid.Thanks Bill


For 6 Volt isolated base (circuit 4) solenoid, SMP (Standard Ignition) # SS-572.

For 12 Volt isolated base (circuit 4) solenoid, SMP (Standard Ignition) # SS-580

ANY local autoparts store should be able to get those part numbers or cross them to the brand they handle.

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There it is. Wore out with the finishing move! Thank you for the part numbers.

When I went through this, these good men correctly diagnosed that i was holding a #3 solenoid and needed a #4. I do not understand the discrepancy when it comes to yt parts though.
 

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