1957 Powermaster, won't start normally

[Rich in NJ]

Last month, while operating my '57 Powermaster (12-volt system, 4-post solenoid), it suddenly refused to start. I hadn't done any work on it recently, so no wires or associated components were touched or disturbed. Since I was in the middle of mowing my pastures, I was able to start it by using a single jumper cable to bypass the starting solenoid. Later, when I had some time, I did some troubleshooting and figured that I had a blown starting solenoid. I bought a new one and upon swapping it out with the bad one, the tractor started right up. About an hour later, when I went for another start, when I pressed the start button, nothing happened. I then bought another solenoid, and this time when it was swapped out, nothing happened when I pressed the button. Now I'm fuming, and what I did learn was that I could disconnect the ignition ("I") and starting ("S") leads off of the starting solenoid, temporarily touch the "I" lead to the "S" post on the solenoid, and the tractor would start immediately and run just as it always had. However, when both the leads were returned to their correct posts, again, the tractor would not start. So, today, I've spent two hours with my wiring diagram and meter, checking for any broken or failed wires - there were none. I also tested the solenoid more thoroughly, and it works just fine and clicks when 12 volts are applied. I removed the cover plate and shifter, and then removed the starting switch and tested it for continuity - it too was fine. I also verified that my key switch was working as well. So, I'm tearing my hair out on just what is wrong! It really seems the starting solenoid is the culprit, but nothing makes sense. Has anyone else experienced this? Any help would be greatly appreciated.

 

[used red MN]

It sounds to me like most likely your starter brushes are nearing the end of life and sometimes don’t make proper contact with the commutator. Or you have a battery cable that has a bad connection hidden under the insulation.

 

[Rich in NJ]

Used Red - well, the starter is fine, as I had it rebuilt about five months ago. All of the heavy cables are also fine, as whenever I jump it to start, it always fires right up. Today, I again spent some time with it, and through process of elimination have determined that the problem is that the start switch wire is not allowing 12 volts to actuate the starting solenoid. With the key on, the ignition wire is delivering 12 volts to the "I" terminal on the starting solenoid, so it's not that. I can disconnect the starter button end of the "S" wire and touch it to the top post of the solenoid (or the positive post on the battery) and the engine fires right up. However, if I then take this same end and touch it to ground - nothing happens. This action should be the same thing as pressing down on the start button, but in this case, it's just not happening. I briefly thought that perhaps my starter button is no good, but it easily passed yesterday's continuity test. Even if the button was no good, I should still be able to get it to start by grounding this same wire, right? Has anyone else experienced this?

 

[Jim.ME]

If you check the S terminal of the solenoid (without any wires on it), does it have battery voltage on it all the time? For the ground provided by pushing the starter button to complete the circuit the pull in coil needs power to it internally from the battery post of the solenoid. If I am understanding correctly the solenoid works when you remove the wire from the starter button and touch the removed end to a power source (the battery cable post on the solenoid). If that is the case it sounds to me like the wrong solenoid. It is also possible the battery and starter cables are on the wrong posts of the solenoid. With all wires off the solenoid do you have continuity between the battery cable post and the S terminal? How about between the starter cable post and the S terminal? Is there continuity between the S terminal and the metal base of the solenoid?

 

[Rich in NJ]

Jim - Thanks for getting back to me on this. I just went out and went through your list. Here's what I found:
1. The "S" terminal does not have 12 volts on it when tested. It's my understanding that it won't until the start button is pushed, as when that happens, 12 volts are sent to the solenoid, and this allows juice to go to that starter and is also sent over to the ignition system.
2. This solenoid is the same type that was originally installed, all three of my solenoids are all the same. Remember, up until recently, the engine started perfectly without any work (electrical or mechanical) done to it for months.
3. The battery and starter cables are in their correct positions, as throughout all of this, the battery cable from the positive post to the top post on the solenoid hasn't been touched - other than to unbolt it from the top post of the solenoid.
4. With all three solenoids, there is no continuity between the battery cable post and the "S" terminal. There is also no continuity between the starter cable post and the "S" terminal.
5. There is continuity between the "S" terminal and the base of the solenoids.
6. Just now, to cover all the bases, I removed, cleaned and reinstalled the negative battery cable, as after owning and operating a 1941 9N (6 volt as well) for over 36 years, I know the value of a good ground. This didn't fix anything, but at least it's one less contributing factor.

Now, am I wrong in thinking that the "S" terminal is supposed to show 12 volts when tested (with the ignition key on)? Is this how it's supposed to work? I do know that the "I" post won't show 12 volts until the key is turned, as this has always been the case when I checked it with my 12-volt test light.

 

[Jim.ME]

Jim - Thanks for getting back to me on this. I just went out and went through your list. Here's what I found:
1. The "S" terminal does not have 12 volts on it when tested. It's my understanding that it won't until the start button is pushed, as when that happens, 12 volts are sent to the solenoid, and this allows juice to go to that starter and is also sent over to the ignition system.
2. This solenoid is the same type that was originally installed, all three of my solenoids are all the same. Remember, up until recently, the engine started perfectly without any work (electrical or mechanical) done to it for months.
3. The battery and starter cables are in their correct positions, as throughout all of this, the battery cable from the positive post to the top post on the solenoid hasn't been touched - other than to unbolt it from the top post of the solenoid.
4. With all three solenoids, there is no continuity between the battery cable post and the "S" terminal. There is also no continuity between the starter cable post and the "S" terminal.
5. There is continuity between the "S" terminal and the base of the solenoids.
6. Just now, to cover all the bases, I removed, cleaned and reinstalled the negative battery cable, as after owning and operating a 1941 9N (6 volt as well) for over 36 years, I know the value of a good ground. This didn't fix anything, but at least it's one less contributing factor.

Now, am I wrong in thinking that the "S" terminal is supposed to show 12 volts when tested (with the ignition key on)? Is this how it's supposed to work? I do know that the "I" post won't show 12 volts until the key is turned, as this has always been the case when I checked it with my 12-volt test light.

To clarify, is your starter button the one by the gear shift lever or something else?

If you hook the clamp of your test light wire to the wire connected to the solenoid from the starter button and put the probe on the battery cable post of the solenoid, then push the starter button. Does the test light light? If so the starter button is providing ground for the pull in coil of the solenoid. Your testing showing continuity between the S terminal and solenoid base indicates that is the wrong solenoid for your system.

There are insulated base solenoids that have 4 terminals and externally look like the ones with a grounded base. On some of those the I terminal gets power from the ignition switch and the starter button provides the ground to make the pull in coil work.

Continuity between the S terminal and base, and you saying that it engaged to operate the starter when you touched the starter button wire to the battery post says it is the wrong solenoid to me. What is the brand and part number of the solenoid?

 

[Eman85]

"Now, am I wrong in thinking that the "S" terminal is supposed to show 12 volts when tested (with the ignition key on)? Is this how it's supposed to work?"
Are we having a terminology issue? Key on means ignition control, nothing to do with starting circuit. You said you have a starting button that is what controls the solenoid.
In your original post you said you were able to use a jumper wire and bypass the solenoid, where did you jump to and from?

 

[Jim.ME]

"Now, am I wrong in thinking that the "S" terminal is supposed to show 12 volts when tested (with the ignition key on)? Is this how it's supposed to work?"
Are we having a terminology issue? Key on means ignition control, nothing to do with starting circuit. You said you have a starting button that is what controls the solenoid.
In your original post you said you were able to use a jumper wire and bypass the solenoid, where did you jump to and from?

If it is an insulated base solenoid with the S and the I terminals used as the leads for the pull in coil putting power to the I terminal from the ignition switch, grounding the S terminal would energize the solenoid. Right now, he has posted he has continuity between the S terminal and base, and in his first post he applied power to the S terminal using the wire from the ignition switch that is on the I terminal to turn the starter.

I am believing the new solenoid may look like the old one, but it is not internally wired the same.

 

[used red MN]

I am believing the new solenoid may look like the old one, but it is not internally wired the same.

I 2nd this motion!

 

[Rich in NJ]

Gentlemen, Jim's most recent post had me return and check things out. Here's what I found:

1. The starter button is the usual factory-installed one next to the gearshift.
2. When I hooked up my test light to the end of the wire that is normally attached to the connector at the base of the start button and then touched it to the battery cable post (with the ignition key on), it immediately showed 12 volts. When I then pressed the start button, it still showed 12 volts.
3. Your comment about there being different types of solenoids (grounded vs. isolated) took me completely by surprise. I had no idea that there was a difference. I had suspected that something was going to ground, this preventing a start, but I couldn't be sure.
4. The solenoid in question is a NAPA ST81, which is a grounded type.
5. Just for the heck of it, I unbolted the solenoid from the frame (with all of the wires & cables still attached) and hoped that with the path to ground removed, the engine would start. I didn't. Perhaps it's failed internally.
6. In any case, would I have better luck if I ordered a P/N: 112395 from YT; this is a 4-post, 12-volt solenoid with an isolated base?
7. It sure seems that I've got the wrong solenoid, however, I still can't explain how it is that the tractor has been correctly operating until recently. And that it did have one successful start with the first one I bought. I guess that it wasn't grounded for all of that time. I'm thinking that I could simply use something to insulate the connection, as then that would allow it to work?

 

[used red MN]

2. When I hooked up my test light to the end of the wire that is normally attached to the connector at the base of the start button and then touched it to the battery cable post (with the ignition key on), it immediately showed 12 volts. When I then pressed the start button, it still showed 12 volts.

Either I am not totally understanding your test process or it has some flaws. When you say “normally attached” I take it you mean you disconnected the wire from the terminal on the start switch, is this right? If you disconnected the wire you will not change any voltage on any wire on the tractor by pushing the start button. To state it to the extreme you may as well be flipping a light switch on the garage wall! Jim’s intention was for you to leave it connected and do the test, to see the response of the circuit.
I don’t have time right now to look up the internal circuit on that NAPA switch. I know someone has posted them before.

 

[Jim.ME]

Good we finally got here. Regardless of whether or not it looks right externally the circuitry inside it is not correct for your application.

The pull in coil of the ST81 is internally grounded to the base. It needs power applied on the S terminal to work and make the starter crank, which it did when you applied power to the S terminal. The I terminal of that solenoid gets energized when the coil pulls in and is used to bypass the ballast resistor to provide full power to an ignition coil during starting, it should not have a wire from the ignition switch connected to it.

You want a NAPA ST542 for a12 volt system (ST541 is the 6 volt version) if you have power from the switch on the I terminal. See the picture below for a couple types of insulated base solenoids. You do not need a continuous duty solenoid like the 112395 from YT.

To make the ST81 work the base needs to be grounded and power must be applied to the S terminal. There is no path to ground for the applied 12 volt power the way you are doing it. You are putting power to both ends of the pull in coil windings. If you powered the S terminal and hooked the starter button wire to the base, with the base not making contact with anything but the wire the starter button, it should provide the ground for it to work when you push the starter button. But why would you, it is the wrong solenoid any way you look at it.

Note: if the starter button wire works as a ground without the button being pushed, it sounds like something is wrong with the start button.

 

[Eman85]

2. When I hooked up my test light to the end of the wire that is normally attached to the connector at the base of the start button and then touched it to the battery cable post (with the ignition key on), it immediately showed 12 volts. When I then pressed the start button, it still showed 12 volts.

Why do you keep turning the ignition on? Which battery cable post are you touching?

 

[used red MN]

Why do you keep turning the ignition on? Which battery cable post are you touching?

I could wait for him to answer I had the same question about the battery cable. But looking closer he was testing per Jim’s request(but not correctly) so I would highly suspect that he was touching the solenoid terminal with the positive cable from the battery on it. I think Jim has solved part of his dilemma by explaining the wiring to make the ST-81 solenoid work that he mistakenly purchased.

 

[sotxbill]

Last month, while operating my '57 Powermaster (12-volt system, 4-post solenoid), it suddenly refused to start. I hadn't done any work on it recently, so no wires or associated components were touched or disturbed. Since I was in the middle of mowing my pastures, I was able to start it by using a single jumper cable to bypass the starting solenoid. Later, when I had some time, I did some troubleshooting and figured that I had a blown starting solenoid. I bought a new one and upon swapping it out with the bad one, the tractor started right up. About an hour later, when I went for another start, when I pressed the start button, nothing happened. I then bought another solenoid, and this time when it was swapped out, nothing happened when I pressed the button. Now I'm fuming, and what I did learn was that I could disconnect the ignition ("I") and starting ("S") leads off of the starting solenoid, temporarily touch the "I" lead to the "S" post on the solenoid, and the tractor would start immediately and run just as it always had. However, when both the leads were returned to their correct posts, again, the tractor would not start. So, today, I've spent two hours with my wiring diagram and meter, checking for any broken or failed wires - there were none. I also tested the solenoid more thoroughly, and it works just fine and clicks when 12 volts are applied. I removed the cover plate and shifter, and then removed the starting switch and tested it for continuity - it too was fine. I also verified that my key switch was working as well. So, I'm tearing my hair out on just what is wrong! It really seems the starting solenoid is the culprit, but nothing makes sense. Has anyone else experienced this? Any help would be greatly appreciated.

Since the i lead makes the selonoid fire correctly... you have NO voltage from the start position of either the ignition switch, or button or whatever..trouble shoot that direction....

 

[Jim.ME]

Since the i lead makes the selonoid fire correctly... you have NO voltage from the start position of either the ignition switch, or button or whatever..trouble shoot that direction....

Did you read all the posts in this thread?

 

[Rich in NJ]

Gentlemen,
First of all, I'd like to thank everyone for their help with this. I know that if we were all standing around the tractor, this problem would most likely have been solved in five minutes or less! In any case, after going through all of these responses, here are my responses:

1. Used Red asked if I had the wire connected to the base of the start button disconnected and hooked up to my 12-volt test light - yes.
2. EMan85 asked why I kept turning on the ignition - this was to ensure that 12 volts were going to the "I" post on the starting solenoid with the key switch on.
3. Jim was wondering if there was a wire coming from the ignition switch to the solenoid - no. The "I" post (or terminal) has a wire connected to it from the switched side of the terminal block.
4. Jim - thanks for the diagrams and the further explanations. I have since ordered a P/N: 311006. It'll most likely show up in the middle of next week. I'll post the results at the first opportunity.

Hopefully this will solve my problem and I can retain most of my sanity!

 

[Eman85]

Might help your sanity, not so much for ours.
I terminal should have nothing to do with needing ignition power to make the starter turn the engine over. How a 1 wire starter button that should normally provide a path to ground could light a test light when touched to a battery post (no idea which post) with the ignition on for some reason is beyond my understanding.

 

[used red MN]

Might help your sanity, not so much for ours.
I terminal should have nothing to do with needing ignition power to make the starter turn the engine over. How a 1 wire starter button that should normally provide a path to ground could light a test light when touched to a battery post (no idea which post) with the ignition on for some reason is beyond my understanding.

Maybe my reply #15 danced around it to much. He did not perform the test Jim requested correctly. Only the fact that he gave the PN of the solenoid, lead Jim to find that that is not proper solenoid/relay if you prefer for this application. The relay he has needs power to the S terminal to engage it. The wire he disconnected and tested was connected to the S terminal. He connected his test light lead to the disconnected wire end. He touched the probe of the test lamp to the powered positive terminal on the starter relay, the lamp lit. His test lamp was showing a ground through the pull in coil winding to its internal ground. Very similar to how an ignition coil shows a ground to its positive primary terminal when the ignition points are closed. The fact that he pushed the starter button was a meaningless effort, it was disconnected.

 

[Jim.ME]

Might help your sanity, not so much for ours.
I terminal should have nothing to do with needing ignition power to make the starter turn the engine over. How a 1 wire starter button that should normally provide a path to ground could light a test light when touched to a battery post (no idea which post) with the ignition on for some reason is beyond my understanding.

Eman85,
If you look at the diagram of the ST541/ST542 solenoid I posted, you will see the I terminal can need to have power to make the starter turn the engine over. If power is applied to the I terminal of that type solenoid the starter button by the gear shift on that tractor is wired to the S terminal of the solenoid and provides the ground for the solenoid coil when it is pushed to make the solenoid send power to the starter.

Rich in NJ,
You said, "The "I" post (or terminal) has a wire connected to it from the switched side of the terminal block." That to me is basically the same as a wire direct to it from the ignition switch, if the ignition switch is supplying and turning the power to that block off and on. With the solenoid wired that way pushing the starter button when the key is off prevents the tractor from being cranked over, which can be a good thing.