Cub Lo-boy 154

grandpa Love

Well-known Member
Strange issue today while mowing. The tractor has a starter/ generator, voltage regulator. Key switch and solenoid. The starter wouldn't stop trying to start the tractor. I removed the key,still turning. Unhooked battery cable and that did it. This happened last summer while cutting grass at church. Figured it was the solenoid, swapped it for a known good one, same issue. Opened the voltage regulator and found a contact stuck,worked it loose, filed it and that fixed the issue. Probably used it 20+ hours since then, including several hours this spring ( 3rd lawn cutting already). Any idea what is going on? Brand new battery,it's charging correctly.
 

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Strange issue today while mowing. The tractor has a starter/ generator, voltage regulator. Key switch and solenoid. The starter wouldn't stop trying to start the tractor. I removed the key,still turning. Unhooked battery cable and that did it. This happened last summer while cutting grass at church. Figured it was the solenoid, swapped it for a known good one, same issue. Opened the voltage regulator and found a contact stuck,worked it loose, filed it and that fixed the issue. Probably used it 20+ hours since then, including several hours this spring ( 3rd lawn cutting already). Any idea what is going on? Brand new battery,it's charging correctly.
The regulator is a (very) compromised device that has responsibility for changing the starter into a generator and vice versa. I believe the best practice is to have a battery disconnect on the battery or big wires so the system can be stopped when it fails because it will. Jim
 
The regulator is a (very) compromised device that has responsibility for changing the starter into a generator and vice versa. I believe the best practice is to have a battery disconnect on the battery or big wires so the system can be stopped when it fails because it will. Jim
Quick disconnect on all my tractors batteries . Any solution to the issue? Just file it and go? Would a new one be better?
 

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Quick disconnect on all my tractors batteries . Any solution to the issue? Just file it and go? Would a new one be better?
New could be better, but trends in VRs tend to be the opposite direction. USA made might be better. Make sure the Gen/starter brushes and frame bushings are good to keep amps correct, and timing is spot on to reduce load on the starter. Jim
 
Strange issue today while mowing. The tractor has a starter/ generator, voltage regulator. Key switch and solenoid. The starter wouldn't stop trying to start the tractor. I removed the key,still turning. Unhooked battery cable and that did it. This happened last summer while cutting grass at church. Figured it was the solenoid, swapped it for a known good one, same issue. Opened the voltage regulator and found a contact stuck,worked it loose, filed it and that fixed the issue. Probably used it 20+ hours since then, including several hours this spring ( 3rd lawn cutting already). Any idea what is going on? Brand new battery,it's charging correctly.
IH was still using cotton wire sheathing into the early 70's and perhaps it has finally deteriated enough somewhere to momentarily short out but not burn out.
Might want to examine the wiring for exposed copper wire(s).
 
That situation gets created in those things from people in the past running a low battery,and trying to start it with a battery charger.A little arcing eats away at those contacts,and when the tractor finally gets a good battery the higher juice tends to arc through the bad stuff,and at some point they will weld themselves together.I would much rather file the weld off and dress up the points than to buy some of the new ones.The International dealer a mile from me sold oodles of those things.Very common problem,but by the time most of them got to me,or somebody like me,the owners had half the wires ripped off.Same story everywhere,if it don't work,rip off some wires and see if that fixes it.
 
Because it's a starter-generator.When you hit the switch it spins,and when it starts and you let go of the switch.Then that contact in the regulator releases when the power to it is killed.That regulator does more than one job.It is a special regulator.I've never really thought too much of the system.For everything to work correctly,and last,you need a perfect battery at all times.On all the ones I've fixed,I bet 9 out of 10 were from people that tried to run the tractors with low batteries.
 
Strange issue today while mowing. The tractor has a starter/ generator, voltage regulator. Key switch and solenoid. The starter wouldn't stop trying to start the tractor. I removed the key,still turning. Unhooked battery cable and that did it. This happened last summer while cutting grass at church. Figured it was the solenoid, swapped it for a known good one, same issue. Opened the voltage regulator and found a contact stuck,worked it loose, filed it and that fixed the issue. Probably used it 20+ hours since then, including several hours this spring ( 3rd lawn cutting already). Any idea what is going on? Brand new battery,it's charging correctly.
Nothing "strange" about that, at all.

Voltage regulator and "cutout" contacts used to be made of various expensive metals and as time progressed, not so much.

Cheaper materials were used or the cutout contacts were made of (relatively cheap) copper plated with a smidge of silver.

Once that silver layer is arced away and/or you file the contacts, and the THIN layer of the "good stuff" is gone, it's all over and welding/sticking commonly occur.

As to the guy that said "When you hit the switch it spins, and when it starts and you let go of the switch. Then that contact in the regulator releases when the power to it is killed. That regulator does more than one job. It is a special regulator", that's total BS/mansplaining, actually the VR isn't involved AT ALL in the cranking process, and no contacts in the VR close during the cranking process, they are very similar to a "two element" VR used on tractors "back when".

What IS special are the field coils in the starter-generator, one is wound with HEAVY "wire" (like a starter) and the other is wound with light-gauge wire similar to the field coils in a generator, which is the compromise in making such a "starter-generator".

It doesn't have the full cranking power of a starter or the full charging power of a generator, it is a compromise between a starter and a generator that can crank a small engine and charge enough (15 Amps or so?), enough to keep the battery in a basic little tractor charged.

There's NO reason to make the Delco starter-generators any more mystical than that!
 
The regulator is a (very) compromised device that has responsibility for changing the starter into a generator and vice versa. I believe the best practice is to have a battery disconnect on the battery or big wires so the system can be stopped when it fails because it will. Jim


"regulator has responsibility for changing the starter into a generator and vice versa"

Nope, regulator has NO function in cranking mode, you can disconnect it and toss it over your shoulder and the starter/generator will still crank when the starter switch is depressed.

Only once the engine starts and the generator begins to charge does the VR come into play, it's cutout closes and it's voltage regulator functions by controlling field current, just like a common "two element" VR on an common full-size tractor of the same era..
 
Strange issue today while mowing. The tractor has a starter/ generator, voltage regulator. Key switch and solenoid. The starter wouldn't stop trying to start the tractor. I removed the key,still turning. Unhooked battery cable and that did it. This happened last summer while cutting grass at church. Figured it was the solenoid, swapped it for a known good one, same issue. Opened the voltage regulator and found a contact stuck,worked it loose, filed it and that fixed the issue. Probably used it 20+ hours since then, including several hours this spring ( 3rd lawn cutting already). Any idea what is going on? Brand new battery,it's charging correctly.
So to be clear......the fact that the points in the voltage regulator were welded together and I unstuck them and the starter quit trying to start the tractor (key out of ignition)....was that the issue....or not? ....im a little confused 🤔
 
So to be clear......the fact that the points in the voltage regulator were welded together and I unstuck them and the starter quit trying to start the tractor (key out of ignition)....was that the issue....or not? ....im a little confused 🤔
The voltage regulator's "cutout points" close while the starter/generator is charging.

When the engine stops, the "cutout points" are supposed to open.

If the "cutout points" do not open/stick, the starter/generator will be cranking the engine.

At a normal shutdown, the "cutout points" open and nothing happens until you press the starter switch.

The contacts in the starter switch are in "parallel"/"across" the "cutout points".

So when the "cutout points" stick, the effect is the same as depressing the starter button.
 
One thing nobody told you to check is your electric clutch. Although I am not familiar with the Cub 154, On later mowers with alternator systems, if the clutch starts drawing more than normal current, it can damage the voltage regulator. The regulator tries to carry the extra current load until it just can't any more and over heats. Just like yours is doing. Being I am not familar with the 154, I am not even sure if they are 12 volt, so I can't even guess what resistance is normal in your clutch.
 
Strange issue today while mowing. The tractor has a starter/ generator, voltage regulator. Key switch and solenoid. The starter wouldn't stop trying to start the tractor. I removed the key,still turning. Unhooked battery cable and that did it. This happened last summer while cutting grass at church. Figured it was the solenoid, swapped it for a known good one, same issue. Opened the voltage regulator and found a contact stuck,worked it loose, filed it and that fixed the issue. Probably used it 20+ hours since then, including several hours this spring ( 3rd lawn cutting already). Any idea what is going on? Brand new battery,it's charging correctly.
Sounds like your regulator is bad. The reverse current relay or better known as the cutout relay has 2 windings in it. As the engine slows down to stop, current starts to flow the other way thru the one winding on the cutout relay, so as the charging current gets less with the low RPM's the reverse current is equal and opposite the charging current which cancels out the magnetic field and lets the cutout relay points open thus stopping all current flow in either direction.
Any generator will keep motoring if the cutout relay sticks.
 
One thing nobody told you to check is your electric clutch. Although I am not familiar with the Cub 154, On later mowers with alternator systems, if the clutch starts drawing more than normal current, it can damage the voltage regulator. The regulator tries to carry the extra current load until it just can't any more and over heats. Just like yours is doing. Being I am not familar with the 154, I am not even sure if they are 12 volt, so I can't even guess what resistance is normal in your clutch.
No electric clutch.... tractor is factory 12 volt
 

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