Electrical problem on Cub Lo-Boy 154 - *solved, that was EZ*

Good morning folks;

I'm new to tractors and new to the board, I was just referred here by the good folks at YTMag forums. I've owned about 90 cars and always done all my own work but I'm a lot more mechanical than electrical...

I have a Cub Lo-Boy that I bought from a friend, it ran last fall when he parked it but wouldn't start this spring. He tinkered for a while, ran short on time, and I took over. I will try to make this short and sweet. I have a manual and a schematic that I have been working with, I've spent a lot of time testing voltage, cleaning connections, and swapping parts, and occasionally drinking a beer and just looking at it (like that would help ).

The tractor will not start. Not a click, not a single noise. What it seems to come down to is that there is no voltage from the outbound side of the starter relay to the generator/motor. I have voltage inbound to the center of the relay via the clutch and PTO safety switch circuits when the key is turned. I have voltage inbound to the relay from the positive cable of the battery (12v+ to each of the above). However, nothing goes out to the generator via the heavy gauge cable on the "other" side of the relay. >I have cleaned and checked all grounds, took an abrasive wheel to the paint under the relay to be sure of the ground on that.
>I have swapped out the relay itself with two others, no change.
> All meter work is done using the grounding stud on the tractor frame rather than the battery post.
> The engine turns well with a breaker bar on the crank pully bolt so it's not locked up.

It has been recommended to recharge the battery and use a set of jumper cables from a fully charged battery to a frame ground and the A terminal on the generator to bypass the switch. I plan on trying this a little later today as soon as it dries out a little, we had rain and it's pretty wet out there.

It seems to my mechanical mind that there is no return path for current flow from the generator and that's why I can't get current out there.

I'm wide open to suggestions and abuse. I'm getting plenty of those from my wife as to why I'm spending so much time out there and none inside with her and the kids so I'd like to solve this ASAP.

I can take photos if it will help and I'll answer any questions best I can. This seems like a very simple machine so it must be something really simple keeping it from even clicking when I turn the key.

Thanks in advance.

Last edited by 888 on Thu Aug 16, 2007 4:33 pm, edited 5 times in total.

If you have voltage to the relay but not from the relay to the starter / generator it would seem that the relay is not pulling in. What I would do first is take a jumper from the 12 volt in to the output terminal to see if the starter will turn. If it does, then you need to re-trace the control circuit to make sure all the safeties are made.
Your thinking on the return path is a little misguided but it's good to know that you are considering all possibilities.
Can you verify that the starter relay is even pulling in?

i have the same exact problem and i havent had enough time to get it totally corrected , at first i thought it was the starter solenoid but now i think it may be a safety switch it was bypassed and i have to pull all the tape off of it and check to see how well the bypass loop of wire is connected . i checked from the bat to the starter and it turn it so that is good .

888:

Well the Electrical Guru (BD) has already posted, and you can trust his advice. I certainly do and will gladly call LD if need be to get BD's advice So with that said, let me carry on with what I do best... I guess: (the server is down at the moment but should be back up today)

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I truly hope that you enjoy your Cub and that you will be a frequent contributor to the forum. Again, to the Cub Family

i have the same exact problem and i havent had enough time to get it totally corrected , at first i thought it was the starter solenoid but now i think it may be a safety switch it was bypassed and i have to pull all the tape off of it and check to see how well the bypass loop of wire is connected . i checked from the bat to the starter and it turn it so that is good .

I'm totally new to this but looking at the schematic and the tractor I think if you have a problem with the safety switches on the PTO or the clutch (they are sort of in series with a bridge from the clutch to the PTO on mine) then you will not have the 12v coming to the small pole on the starter relay via the orange wire. Those switches need to be made before the starter relay will pull in. I think the clutch switch is normally open and made when the clutch pedal is pushed against the plunger. The PTO is normally closed and opens when the PTO handle comes up. I had a bad clutch switch and the PTO switch wires were sheared off when I got this one so I had to redo all of that some time back. I jumped across the leads going into the clutch switch until I got a new switch.

I have the 12v to the starter switch when the key turns but there is no sign that the relay is working.

I've got 12v to the BAT on the voltage regulator too.

My guess is that your problem is in the control circuit. You will basically need to trace it wire to wire until you find the break.

If you have voltage to the relay but not from the relay to the starter / generator it would seem that the relay is not pulling in. What I would do first is take a jumper from the 12 volt in to the output terminal to see if the starter will turn. If it does, then you need to re-trace the control circuit to make sure all the safeties are made.
Your thinking on the return path is a little misguided but it's good to know that you are considering all possibilities.
Can you verify that the starter relay is even pulling in?

Thanks for the reply BD.

I have 12v coming in from the positive cable on the battery on one side of the switch.

I have voltage (12v) from the safety switch circuit to the small terminal/pole on the starter relay/switch via the orange wire when the key is turned. There is no sign of life on the outbound lug for the cable going to the generator/starter terminal A or to the terminal A. No clicks, no beeps, no boops. Nada. I have never been able to get the smallest sign of life. I have had at least 10 AHA! discoveries when checking switches and wiring that I thought were going to make it do soemthing and none have done squat. That's why I'm thinking it must be something really basic. I cleaned the paint behind the relay so I was sure it was grounded to the bulkhead wall behind the dash. I've swapped relays twice. Neither had any sign of life so I looked elsewhere.

I put a small jumper wire across the two terminals on the starter switch and nothing happened starter wise when I installed the battery neg post cable to fire things up. I've been doing this for weeks so some of the details on early trials are a little foggy but I know it did it.

What I was thinking of doing is reinstalling the battery after it is done charging and leave my meter on the battery posts when I turn the key and see what happens with the battery. If there is no current drawdown, then that should tell me something, right? If it draws way down, that should tell me something else.

Yes, i can be a little misguided but I will probably be no end of fun for you guys to witness while I'm on the wrong path and I'll learn something along the way.

I'm a hands-on mechanical guy, I know machine control automation and I/O logic, I just don't ever get to do any hands on electrical work. so this is a really good exercise, I'm just not used to checking for electrons. The only thing I go by is that current needs a path via grounding to flow. That's why I wondered about the grounding at the generator. If there's no place for the current to go, it won't leave the switch.

So, what do you think?? I'll post what I learn today from the battery test, I'll try something else if you suggest it and my fear of voltage allows it.

888:

Well the Electrical Guru (BD) has already posted, and you can trust his advice. I certainly do and will gladly call LD if need be to get BD's advice So with that said, let me carry on with what I do best... I guess: (the server is down at the moment but should be back up today)

....

I truly hope that you enjoy your Cub and that you will be a frequent contributor to the forum. Again, to the Cub Family

Thanks for the info Rudi. I wish I would have found you guys a few weeks ago, I've already made a few bad choices on documentation. I'll pay attention and look here first in the future. If/when I get this running, I'm going to go through it so I'll need sources for a lot of stuff.

Joe

Does anyone have a circuit diagram for the 154? I'm flying blind here trying to visualize the circuit.
The only thing that comes to mind is whether this is the right relay and if the wires are on the right terminals. If I understand things correctly, you have voltage to the control coil with the switch on and yet it does not pull in. If you jumper from battery to armature does the starter spin?

Here you go.

http://ihregistry.com/wiring/K16.pdf

Thanks Don. That helps a lot. When the key is in the start position voltage should be present at the black/orange wire on the solenoid. When voltage is present there, the solenoid should pull in providing voltage to the armature. Taking a jumper wire and momentarily connecting battery plus voltage to the terminal where the orange & black wire connects to the solenoid should activate it. Can you try this test?

888:

You and BD are checking the starting circuit correctly. You have voltage on the battery side of the solenoid and when you turn on the ignition key you have voltage to the center (small) terminal on the solenoid. And no voltage on the output side of the solenoid at any time. You also stated that you have changed out the relay (solenoid) several times.

You either have a bunch of bad solenoids (relays) or a dead battery.

Replace the battery with a known good one.

You can do a voltage drop test on the current battery. Connect your voltmeter to the battery then try to start the tractor. My guess is the battery will read 12 volts with the ignition switch off and 3 or 4 volts with the ignition switch in the start position.

Eugene

Thanks guys. Thinking back, I had the exact same thing happen on one of my VW diesels (usual tinkering target) overnight and it was the engine grounds. Switch off one night fine, next morning nothing at all, just like this one.

So I decided to reground the battery. I put the braided neg cable end in between the battery tray and the fender after using an abrasive wheel on the cable end and sanding where it meets the fender and tray. Previously I had it grounded on a nut threaded on the back side of the bolt holding the tray on the fender.

I charged the battery this morning and took it off the charger reading 12.94v between the posts with a VOM.

I installed the battery after doing the grounding work above and it read right around 12.54v after installed. I get a little sizzle off of the neg cable when popping it on there, I assume that's the active circuit through the ammeter. This is all the same, no change, right down to the 12.54v reading.

I turned the key and there was no change on the VOM, it stayed right around 12.54, might have dropped down to 12.49 briefly but flickered back up to 12.54. I really expected it to drop off and it didn't move. The ammeter doesn't react to the key either, but it does when I turn the lights on. (It has been replaced too, the original didn't work and was bypassed when I got it).

I doublechecked the presence of ~ 12.5v at the black/orange lead coming in to the center post of the relay. It's there when the key is turned to start and it's not there when the key is in off or run. So the safety circuit is working. and there is ~ 12.5v at the pos battery cable side of the relay.

So what does this tell you guys? Maybe I have two bad starter relays????? There's a part number on one of them, don't know if it's the one in the tractor or the spare. I remember these things from my old Fords, they usually went bad at some point in time. Are they special to the Cub, they look pretty typical, I wonder if I could get one from Autozone or something.....it's just a relay.

I'm a little gun shy with cables and voltage, so I guess the next move is to try to jumper cable from the battery pos cable to the A terminal on the starter generator or is there something else I can try?

Thanks for the help. I'm trying to bring this poor thing back to life, it's having a lot of fun being dead apparently.

EDIT and PS. My oil light doesn't work either when the key is on run. The instrument half of the 8 pin modular connector is new, I got one from Carter and Grunewald a few weeks ago, the old one was too hacked to deal with

The schematic linked above is different than mine (IH23) but it looks to be the same functionally. I also have CASE/IH Service manual GSS-1408 for the 154, 184, and 185.

Last edited by 888 on Sun Jul 29, 2007 3:00 pm, edited 1 time in total.

It sure sounds like a bad solenoid to me. The test you were going to perform can be done at the solenoid rather than right at the starter. Just touch a jumper across the terminals with the black wires on them and it should start. One thing that is not right though is the slight arc when you connect the battery cable. There should be no load on the battery. You didn't have the switch in the on position when you connected the battery did you?

The shortest logic is this: you have voltage to the solenoid control terminal. It is not activating for some reason - either it's bad or it has a bad ground. Or, you have the wires on the wrong terminals of the solenoid.

It sure sounds like a bad solenoid to me. The test you were going to perform can be done at the solenoid rather than right at the starter. Just touch a jumper across the terminals with the black wires on them and it should start. One thing that is not right though is the slight arc when you connect the battery cable. There should be no load on the battery. You didn't have the switch in the on position when you connected the battery did you?

The shortest logic is this: you have voltage to the solenoid control terminal. It is not activating for some reason - either it's bad or it has a bad ground. Or, you have the wires on the wrong terminals of the solenoid.

Thanks BD.

I did that jumper test across the poles of the relay some time back thinking I could bypass the relay and nothing happened, I can do it again.

There is a slight snap, very small, on the neg post. I'm a wuss around sparks and this one doesn't scare me so you know it's small. The key is always out of the ignition or in the off position. I give it a little pull to be sure it comes out and it's really off. I've always had this little snap happen on a car, there's usually an active circuit somewhere, clock/memory lead or dome light. It's like that, really tiny.

The solenoids are directional? They are not marked at all, I didn;t think it mattered. I've been putting them on the same way as they were when the tractor arrived. I thought the 12v on the center post fired an electromagnet and made a connection between the two posts to let current flow, I really didn't think direction mattered.

I can take the relay back off and use the 3M wheel to take some more paint off behind the relay backplate. Its bare metal back there now.

I agree it seems like a ground based on my car based example, I just don't know where the ground problem is. Maybe I should get a new neg cable? I have one of those old braided style, it's pretty solid but old.