RTV 400 giving shock touching metal frame?

[abedlamite]

My RTV has an electrical issue somewhere and I'm not sure what's causing it. I first noticed inconsistent starting, where the starter would engage but struggle to turn the flywheel, but then the next two or three starts would be crisp and perfect. I ruled out the battery (it load tested fine at O'Rileys, but put on a new one anyway which registered 14v while the RTV was running). Then I noticed that if I was touching the roll bar while I switched off the key, I would get shocked. Then, occasionally, I would get shocked if I touched the metal roll bar while it was running. And now the starter is completely dead. Turning the key makes no sound for several seconds before I can hear the flywheel try to turn with a tiny grunt, then nothing. The fuel pump still primes with the key half-turned, and the battery is still registering fine. I had to tow the RTV back to the house because it died on the trail (of course) and ordered a new starter.

Any ideas for the shocking? I'm assuming something is grounding out on the frame, which might have contributed to the starter problems, I'm just not sure where to start. I would say the ignition switch, but there are so many other wires on this thing I'm feeling a little overwhelmed. In any case, I can't test or find it until I get the starter out and replaced.

I also replied to an older thread about replacing the starter, because I can't get the damn flywheel off to remove the two screws for the starter... If anyone has tips or tricks https://www.orangetractortalks.com/forums/threads/400-rtv-starter.54601/#post-586424

 

[Mark_BX25D]

Check your grounds.

Check the battery cables and connections, both ends. This does not mean "glance at the top of the battery and if there's no obvious corrosion you are good". It means TAKE IT APART AND CLEAN IT. And do not overlook the ground connection to the frame, and the hot connection to the starter. People often make that mistake. "Battery's good, must be something else." Nope, BOTH ends need to be good.

And while you are at it, very carefully inspect the cables. Again, both ends. Corrosion can wick up inside a cable and rot it from the inside out. It's not readily visible from the outside. Look at the exposed end of the cable. Do you see corrosion there? If so, the cable may be bad. One way to find out is to get rough with the cable. Twist it, push it, bend it. If it feels at all "crackly", replace it. "Oh, but if I get rough with it, I might break it!" Good! If it's a good cable you won't bother it. If it's borderline, you want to break it.

 

[Roadworthy]

Mark covered it all very well. Give extra attention to cleaning and tightening the ground cable where it attaches to the frame. Getting shocked touching the frame or roll bar suggests something is amiss with the system grounding.

 

[Nicksacco]

Did you ever solve this?
I had a thought that somehow the 12V it uses was somehow increased by a coil. Kind of like a spark plug coil or similar.
You said it shocks you running or not. Something is drawing power when engine is not running.
Does it matter if the key switch is on or off?

I'm thinking voltage leaking from secondary from a transformer (coil) of some kind? Starter coil?

 

[jkrubi12]

It's obviously a ground issue, the suggestions above are very good to resolve such issues.

I would also add the following; I would carefully inspect any aftermarket or user-added electrical components, e.g. lights, winch, etc...Even dealer-installed electrical components could be a source of the problem. Follow the diagnosing instruction from the above posts in any 'extra' component inspection(s) and eliminate any potential issues.

The level of the shock received from the roll bar is also an indicator of the source of the problem; a 'light' shock vs a 'heavy' shock could point to a lower-voltage grounding issue (lights, etc) rather than a major component drawing larger current (starter, winch).

Finally, I would not rule out the starter as a source of the issue; There's a lot of metal-to-metal contact in the attachment of a starter and if it's 'going bad' it could be a source of electrical malfunction that's not easy to see. Good luck!

 

[ctfjr]

As others have well pointed out it looks like there is a continuity breakdown between the ROPS and other parts of the chassis.
As you mentioned turning the key off and touching the ROPS resulted in a shock, the only thing I can think of that might cause that is the collapsing magnetic field of a relay - coupled with the bad ground problem.
I think the ground issue is most likely between chassis components. That's why, when I ran 12 volts to the rear of the tractor, I didn't just use the chassis as a ground but ran a separate wire from the battery negative (and also attached it to a rear chassis component)

 

[Vigo]

ASE Master Tech here, i teach automotive for a living.

It's basically impossible for a 12v system to 'shock' you. If you've ever held a 9v battery to your tongue, you can imagine 12v would be, oh... 33% worse than that. STILL not enough to shock you through DRY skin, although you can sometimes feel it if you are sweaty. Usually it takes well over 30v to 'shock' you. I have 'felt' the 25v from old phone landlines, pretty mild.. I have a 48v battery system powering my offgrid house and OSHA considers under 60v to be 'Safety Extra Low Voltage', so hopefully this is getting across that you are probably not being 'shocked' by the 12v system.

However, you can be shocked in other ways. Static electricity buildup (unlikely), or the spark ignition system (more likely). There's also a tiny chance there is some other large electromagnetic device on the vehicle like an electric pto clutch or something which could cause this, because any electromagnet creates a voltage spike on the line when it is 'turned off', which on a 12v system can go over 70v. This is how the ignition coil itself works, except it is also a transformer which steps voltage up into the 10,000+ range.

The way ignition systems generally work is that high voltage on the center electrode of a spark plug when the ignition coil is switched off, causes a spark to jump to the ground electrode which is welded onto the outer shell of the plug. Jumping the gap causes almost all the voltage to drop, and the current flows through the spark plug threads into and through the engine itself, through the ground wire of the engine, back to battery. How it gets from there back to the 'source' (ignition coil) is counterintuitive and pointless to talk about here. So in a normally functioning system the only high voltage is between the coil and spark plug.

However, voltage drops proportionally to resistance, so if the ground path picks up a bunch of resistance because of poor connections, some of the voltage that dropped across the spark plug gap will drop at the location of that new resistance instead. The spark itself will be weaker (because less voltage is being 'converted to spark'), and there will now be voltage on the portion of the ground circuit between the spark plug threads, and wherever this new resistance is. It doesn't take a very high percentage of 10,000v to be 'shocking' to a human. If you've felt 120vac inside a house, you know 120v is well past 'enough' to shock you and that's still only ~1% of 10,000v.

So yes, it is a ground issue. The ground path from the spark plug threads to wherever the ground wire comes out of the engine, is basically bulletproof because the engine is a honkin chunk of metal that doesn't just fall apart or rust to pieces. So you need to focus on everything between where a ground wire leaves the engine, and where that path finally ends at the negative battery terminal. This is also the ground path for the starter, which explains the weak crank/no crank happening at same time as getting shocked when you turn the key off.

Some engines have a ground wire that goes direct to battery negative, and if that path fails the spark circuit will try to find an alternative ground path through the engine mounts or possibly exhaust system hangers, into the 'frame' of the vehicle, through frame to wherever there is a path from frame to battery negative. You might be becoming that path by touching two different parts of the frame (one side connected to engine, one side connected to battery negative).

Regardless, when you fix this ground problem, it will stop shocking you AND start running consistently again. If just cleaning the battery terminals doesn't do it, i suspect if you look at the engine and simply find the large ground wire leaving it and follow that wherever it goes, you will quickly find the issue.

 

[Mark_BX25D]

It's basically impossible for a 12v system to 'shock' you.

Not true.

I've been shocked by 12v, and it was a pretty good shock, too. It all depends on the conditions.

 

[Henro]

Not true.

I've been shocked by 12v, and it was a pretty good shock, too. It all depends on the conditions.

Kind of doubt that. Not doubting that you were shocked, but rather that it was 12 volts that did it.

How do you know this? Did you make a measurement or are you just assuming?

My guess: Just assuming...

 

[Mark_BX25D]

Kind of doubt that. Not doubting that you were shocked, but rather that it was 12 volts that did it.

It was 12 volts. I was installing equipment in a mid-sized American car. I didn't need to measure since the battery was the only power supply involved. The car was not running, so it could not have been a runaway alternator. No, there were no capacitors involved. I was sweaty and got my hand between a hot spot and a ground up under the dash.

As you said, stick a 9 volt battery on your tongue. If 9v will shock you (and it WILL), 12v will shock you.

 

[lugbolt]

A good friend died when he was changing the battery in his truck. Sweaty hands, and he had a pacemaker.

it is possible, though very rare.

 

[Henro]

A good friend died when he was changing the battery in his truck. Sweaty hands, and he had a pacemaker.

it is possible, though very rare.

I told my doctor that I thought I was having a reaction to the covid virus shot, and he said "coincidence"...it was a mild dermatitis issue...

No way to know for sure the cause of your friend's death. It could have been exertion.

People die shoveling snow each winter. I suppose they could claim it was the result of a shock cause by the cell phone in their pocket...

I do believe anything is possible though...no argument there.

 

[The Evil Twin]

Fibrillation can occur with as little as 400mA DC. It doesn't take much to stop a heart under the right circumstances. Sweaty hands and clothes crossing two battery terminals (right across the heart)? I could see it happening to someone with a pacemaker. Especially if the car is running.

 

[Henro]

Fibrillation can occur with as little as 400mA DC. It doesn't take much to stop a heart under the right circumstances. Sweaty hands and clothes crossing two battery terminals (right across the heart)? I could see it happening to someone with a pacemaker. Especially if the car is running.

400 mA is a LOT of current, almost a half amp! Well under 100 mA is enough to kill a healthy person if it crosses their heart. At least something that was taught in safety meetings when I was working, and never had any reason to doubt it. I want to remember that the number was considerably smaller than 100 mA.

While we are beating this horse, some may find it amusing how my high school shop teacher taught his students about electricity. He had us all stand in a circle, all holding hands, and chose two students to break the circle, and put a wire in each of their hands, and plugged it into a 120 VAC outlet. You could feel a tingle in your chest. He said, that is Electricity! Now you have experienced it...

This is honestly a true story...

 

[The Evil Twin]

In theory, the AC current required is less that DC current. Don't know why though. I'm not a heart doctor, but I've broken a few

 

[Henro]

In theory, the AC current required is less that DC current. Don't know why though. I'm not a heart doctor, but I've broken a few

I think you are correct. I remember once I was working on a breakdown in a steel mill, and it was extending into close to 24 hours (complex control system) and I was tired and yawned.

But the passage way was narrow, and on one side was a 250 VDC control panel, and the other side was the steel building frame. Intuitively I suppose, when I yawned I extended my arms...BINGO! No longer sleepy when one hand touched the 250 VDC and the other touched the building frame!

 

[Vigo]

He said, that is Electricity! Now you have experienced it...

Holy crap! I don't think i could get away with that today..
But would it surprise you, that MORE THAN ONCE, students have brought cheap little stun guns into class and shocked themselves on a dare? Because i am no longer surprised.

Condolences about the friend with the pacemaker.. I currently have a student with a pacemaker who just had her battery replaced and was out for a week, and we discussed the issues to the best of my knowledge. I hope i am not leading her astray.

I don't claim to have a perfect understanding of electricity, but i think some of it comes down to semantics too. For example some people think you should never use the word electrocution unless someone died, and i think that's not the way it's commonly used by the layperson etc. But yes 12v can cause 'perceptible current' if you have wet skin or open wounds (usually just sweat) and i've felt that. It's uncomfortable but i think most people could do it on purpose and 'stay on it' and keep a straight face and not make any noise, if you bet some money on it. I think it's mostly just our reflexive reaction to it that makes it seem dangerous, and if someone put some electrodes on your sweaty hand and said im gonna crank it up slowly until you tap out, plenty of people would get past 12. It's possible if they put those electrodes directly on your heart it would be dangerous, but if it was at all likely for anyone to be seriously injured by the current flow through their body from 12v, people would be getting seriously injured all across the globe, all the time!

In my classes i do talk about the danger of reflexes! Just a couple of weeks ago i told some students "if i was climbing a ladder onto my roof and just as i got near the top a housecat on the roof jumped on my face and started clawing and biting me, there's a good chance i would die" and how our reaction to the thing can be much more dangerous than the thing itself. In NON-automotive electrical training you would get a line like "all housecats should be treated as potentially lethal", but in my years i have NEVER heard anyone beside myself ever bring up the ways a housecat can kill you.

So i feel like 12v is like the housecat. Sure, there's probably a way. But it's a fringe scenario that has more relevance to a devil's advocate who will try to pick it up and make a 100yd dash with it in conversation, than it has any relevance to your actual health and safety in real life. I hope i am not wrong.

 

[lugbolt]

I told my doctor that I thought I was having a reaction to the covid virus shot, and he said "coincidence"...it was a mild dermatitis issue...

No way to know for sure the cause of your friend's death. It could have been exertion.

People die shoveling snow each winter. I suppose they could claim it was the result of a shock cause by the cell phone in their pocket...

I do believe anything is possible though...no argument there.

nope it was guaranteed COD, verfied by autopsy. Bad deal. At one point there was a big deal "online" about it and few believed it.

I just went through some MORE training on EV's for work and there was a whole great big section of a LONG training session about DC voltages and how they can be dangerous, but usually aren't. It's a big deal with EV's because of the amount of current involved. The ones I'm messing with are upwards of 300v MAX, some are up closer to 1000v but I probably won't see much of that. And amperage....thousands. And a lot of folks don't know that the US OSHA requires that EV techs have a dedicated roped off work bay, tons of specialized insulated tooling, different kinds of PPE, and in some instances, a SECOND tech in a mostly supervisional role, in order to work on them. So maybe if a tech has to replace a high amp cable, maybe that's normally 1.0 hour labor, just became 2.5 hours and it might only take 22 minutes or however long. But EV proponents will NEVER tell you of this stuff. Mostly because 99% of them have no clue, and the techs that do have a clue, don't talk about it. Anyway in the class they talked specifically about this exact thing (high voltage and current) causing shock and such, going on to say that if you have a pacemaker, you're better off as a supervisor.

OH something else they mentioned, and I've known of this for a while because I have to do it. OSHA requires EV techs to wear certain PPE when working near parts of the EV, and some of that PPE is to be re-certified every so often. I think they charge is $50 with shipping to recert. Add that to the cost of the repairs of course. I imagine some techs (and shops?) will ignore this because of cost and inconvenience.

high tension leads are another story. My race car is a great example. It was sitting there on stands idling (1400 RPM) and I was adjusting the timing. Grabbed the distributor and the next thing I remember was waking up with someone's arms around me and TERRIBLE chest pains. Don't know why I passed out but it wasn't no fun. Neither was the heart issue; that HURT; but wasn't worse than having a bad case of pericarditis.

 

[Fordtech86]

And a lot of folks don't know that the US OSHA requires that EV techs have a dedicated roped off work bay, tons of specialized insulated tooling, different kinds of PPE, and in some instances, a SECOND tech in a mostly supervisional role, in order to work on them.

I think that’s recommended by the manufacturer here in the US, but not required by the US government

 

[Vigo]

Lugbolt, as far as i know everything you just said is true. I hold the ASE L3 'hybrid' cert and am actually the lead on developing a hybrid/ev curriculum for our automotive program. I've still never heard of anyone who died from 12v, although the pacemaker is probably the key factor there.

The PPE requirements for EV/hybrid are pretty strenuous, but it's nothing unusual for linemen and other people who routinely spend entire careers working on high voltage circuits and live through it. I think the main thing is to truly believe that it CAN kill you, so you don't have to 'work yourself up to' being careful, and it's just something you want to do out of respect for all the people who would miss you.

The ppe requirements for 12v are usually zilch, but if one WAS concerned about it, basically anything would work. Leather gloves. Even disposables, as long as you don't tear it. I would hate to put an unreasonable fear out there that every single person with a pacemaker should be concerned about dying if a situation like the OP's should happen, a ground problem on an engine.. that's NOT an uncommon problem! And basically EVERY vehicle that normal people make contact with, is 12v and chassis ground. So while I won't argue the circumstances of your friend's death, I also don't know if it moves the line in the sand in a way that i should be teaching safety differently. I'm open to opinions. I do have a student with a pacemaker in an electrical class right now.

Here's a good video about high voltage hybrid/ev safety equipment if anyone's curious: