Farmall 656 Hydro ignition problems.

surveyor33

New User
Tractor wont stay running after I release starter button. I have already checked switch, replaced starter button.I was told it may a bad resistor. Where is this resistor located? I don't see it anywhere near the coil or in the harness leaving coil. this tractor has the alternator also, not a generator. already by passed clutch saftey switch also. Ran new wire from solenoid to key switch also still no luck .
 
Sounds like the ignition bypass wire is the only wire feeding your ignition coil. This wire goes dead after the starter isn't running any more. This wire was originally used to bypass the ignition resistor.
You need to find the ignition terminal on your key switch and follow it. It should lead to the resistor then from there to the coil. If this wire has no resistor in its circuit then you most likely have an ignition coil with it built in it.
 
It could also have a "resistor wire" instead of a ceramic resistor. Follow the wire from the coil and see if it turns into a single strand wire. It could be broken either at the coil end or the switch.
 
Also thank you John for your help I have another question is the voltage regulator built in the alternator or is it in the dash behind the battery?
 
(quoted from post at 17:26:56 02/01/14)
(reply to post a
t 12:52:30 02/01/14)
would that mean my coil is bad then if the resistor is built in
o. It starts, so that alone says, "coil is good".
Why not take 20 seconds to prove that the problem is between battery & coil, then you will KNOW where & what you are looking for instead of just looking. How, you say? Connect a temporary wire from non-grounded battery post to input (non-distributor side of coil). Start it & if it starts & keeps running, then you will know where to look for an open circuit.
 
AS for the alternator, it was factory equipped with a 10DN Delco and an external regulator. The regulator is located behind the right rear corner of the fuel tank up under the cowling. Fifty years later who knows what has been done.
 
Thank you. Between you and John I think I can get this figured out it is my fatherinlaws tractor he bought it new and every thing is original so nothing is jury rigged.
 
John still no luck have did everything traced it back till I cant get to it no more. No power at coil. My next question is the coil picks up power from the I terminal on solenoid but I have no power there either, only when I hit the start button. where does I on solenoid pick its power up from? inside the solenoid or from a different source my schematic don't tell me
 
(quoted from post at 15:47:23 02/02/14) John still no luck have did everything traced it back till I cant get to it no more. No power at coil. My next question is the coil picks up power from the I terminal on solenoid but I have no power there either, only when I hit the start button. where does I on solenoid pick its power up from? inside the solenoid or from a different source my schematic don't tell me
es, contacts inside solenoid.........stop looking there....that part is working.

I guess I will repeat:
Why not take 20 seconds to prove that the problem is between battery & coil, then you will KNOW where & what you are looking for instead of just looking. How, you say? Connect a temporary wire from non-grounded battery post to input (non-distributor side of coil). Start it & if it starts & keeps running, then you will know where to look for an open circuit.
 
John the reason I asked that question is because my schematic shows the coil gets full power from the I terminal on solenoid. I jump coil from battery it stays running I traced back as far as I could see and reach and that is what I come with I just thought something shorted out in solenoid because I isn't energized when I turn the key on and that's how I understand the schematic to read. Besides this tractor is in a decrepit barn no heat was just trying to make sense of it because we had the starter get caught and I had to disconnect it from power because key wouldn't shut it off. we then had starter rebuilt but they didn't replace solenoid just thought something shorted out in the solenoid from being caught on and spinng so long
 
(quoted from post at 17:28:28 02/02/14) John the reason I asked that question is because my schematic shows the coil gets full power from the I terminal on solenoid. I jump coil from battery it stays running I traced back as far as I could see and reach and that is what I come with I just thought something shorted out in solenoid because I isn't energized when I turn the key on and that's how I understand the schematic to read. Besides this tractor is in a decrepit barn no heat was just trying to make sense of it because we had the starter get caught and I had to disconnect it from power because key wouldn't shut it off. we then had starter rebuilt but they didn't replace solenoid just thought something shorted out in the solenoid from being caught on and spinng so long
don't have your schematic, so 'absolute' certainty isn't guaranteed, however, it is about a 99.44% certainty that there is a wire (probably resistive at about 1.5 Ohms) coming from the ignition switch to coil. Now it may not take a direct path. For example, it could run from ign sw down to the small solenoid terminal & from that small solenoid terminal on to the coil. That ign switch to coil, by whatever path, is going to be your problem.
 
(reply thttp://www.cngco.com/wiring_diagrams/IH%20656-666-664-686.pdfo post at 14:36:56 02/02/14)
ohn here is where I got diagram from and thanks for your reply I will trace wires from the I terminal on solenoid back tomorrow. I kinda got put up to fixing this by my father inlaw its his tractor he's in no rush and I love helping him,but with working in these cold conditions I get frustrated but I like to see things through.if you want to look at the schematic I am using follow the link I sent. It is the farmall 656 with alternator one. And again thank you I will plug away again tomorrow
 
(quoted from post at 15:17:07 02/02/14)
(reply thttp://www.cngco.com/wiring_diagrams/IH%20656-666-664-686.pdfo post at 14:36:56 02/02/14)
ohn here is where I got diagram from and thanks for your reply I will trace wires from the I terminal on solenoid back tomorrow. I kinda got put up to fixing this by my father inlaw its his tractor he's in no rush and I love helping him,but with working in these cold conditions I get frustrated but I like to see things through.if you want to look at the schematic I am using follow the link I sent. It is the farmall 656 with alternator one. And again thank you I will plug away again tomorrow also the terminal that I call is labeled[ R] the mechanic I talked to said for ignition
 
OK, you will need to refer back & forth between the diagram in your link & the marked up one here, since my mark up is not readable as far as wire colors. The colors that I marked have no correlation to actual wire colors, but are just to allow us to communicate. Someone has penciled a resistor symbol in the black wire (my blue) toward upper right. I do not expect that this is a correct location, because the power to start switch button/safety sw/solenoid start input would have to flow through a resistor if in that position & that is highly unlikely. With the wiggle/purple line, I am indicating where I expect the resistive wire to be. If & that is always an 'if', the physical wiring is like the schematic, then it looks like the resistive wire may splice into the wire running from solenoid R(I) terminal over to the coil. I have circled a junction at intersection of ign sw output wire (my blue), the wiggle (my purple), and a wire dropping down to regulator #3.....it is very likely that this is the beginning of the resistive wire.
If you can't find the resistive wire or it becomes too much of a hassle to do so, then there are two alternatives, 1) tap into the switched ign wire (my blue) at any accessible point with regular copper wire & install a ceramic ballast resistor in this new wire & beyond the resistor, connect either to coil or to R(I) terminal on the solenoid. 2) Since that resistor (~1.5 Ohms) will likely cost about half as much as a new NAPA IC-14SB coil (requires no resistor), then you might want to replace current coil & skip the resistor. Now just a new copper wire & new IC-14SB. Hope helpful.
 
ok that's what I was thinking of doing. in case the stock wire has a dead short should I take and unhook it from the coil and leave it out of the loop when I run the new wire from the resistor to the coil?
 
(quoted from post at 21:41:55 02/02/14) ok that's what I was thinking of doing. in case the stock wire has a dead short should I take and unhook it from the coil and leave it out of the loop when I run the new wire from the resistor to the coil?
hat might be ideal, but if it is doing nothing as it appears, then it probably doesn't matter
 
Just thought I would let you know I got it going. Went with the Napa coil and new wire and she fired right up. Just happy to have it done and back together. Thank you again for all your help. :D
 
(quoted from post at 15:52:13 02/03/14) Just thought I would let you know I got it going. Went with the Napa coil and new wire and she fired right up. Just happy to have it done and back together. Thank you again for all your help. :D
xcellent! Glad to be of help & thanks for the feedback.
 

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