super c VR issues

I've noticed the ammeter doing funny things the past few days. At 3/4 to high idle, shows 0 to 1 or 2 amps charge. Below about 1/2 speed, shows 4-5A discharge. if i ground the F terminal, it charges like crazy- 10A at low idle, buries the needle at 1/2 or a little higher. so i think that means the gen is good. almost seems like the VR is set for too low a voltage setting. i've had the tractor for about 10 years and replaced the VR 2 or 3 times already. the tractor has never been one to charge at high rate, even with discharged battery- 4-5 would be the most. with lights on high it will show a discharge at low rpm, up to +1 or so at fast speed. so i'm thinking maybe the VR has never been quite right?

Couple of things does your gen have the third brush thats adjustable as it will set the charge rate. Does your regulator mount on the gen or an a bracket below. Do you know the number on the tag thats on the generator. There are two regulators that can be used on the C it depends on your generator. First i would check the generator for the third brush then go from there. Depending where you get the regulators they mite only list one.

pretty sure it's the 3 brush gen. i'll check on the number. the reg mounts on the bracket below.

I agree - the VR's the problem. (Your tests confirm the generator's in excellent health...)

Before you replace the VR however try running a temporary jumper wire from the reglator base to the grounded battery post. If charging improves clean up the ground at the regulator, or install a permanent ground wire. Otherwise time for a new regulator!

Maze, I dont think its any third brush adjustment problem, cuz if she charges that well with a dead grounded Field that says the genny (including wherever its third brush is set) is fineeeeeeeee PLUS the gennys ground is fine. I agree with my buddy the Bob M, before tossing the VR make sure it has its own good ground by jumping its case/frame/metal to a good ground n see if charge improves??? (also check n clean the VR's F terminal to gennys FLD post wiring for a loose or resistive connection) If not you may be able to non abrasively as possible clean/buff/polish the VR's field control relay contacts cuz they may be burned or carboned n resistive, worth a try (grounding and cleaning).....

Ol John T and all

You may try using a voltmeter to set the voltage before replacing the regulator. With the cover off, put a little pressure on the points next to the field terminal. If the voltage and amps increase tighten the spring tention until you get about 7&1/2 volts. Check again with the cover on , it may change a little.

I agree Teddy, The likely factor is the spring tension (it takes little change to fix the issue.
I recommend taking off a battery cable when doing this to assure safe removal and install of the cover.
Many have had smoke let out when the cover grounded the cutout contacts. Reconnect to test with the cover off. If this makes no difference, or you do not feel in a tinkering mood, do as Our good friends John T and Bob M indicate. JimN

the D-R tag on the genny says 1100501 4?30 can't quite make out the ? digit, might be C,G,O, or zero. anyway the parts book lists 1100501, and a 3rd brush.

on the VR ground- tried a jumper wire from the little copper wire on the VR that goes from the base to the mounting tab, to the tractor frame- didn't help at all. the F to FLD wire idea sounds worth a shot- i'll see where i get with that. The new VRs these days don't have any adjusting screws for the spring tension, and it seems like the past few i've gotten were not set at correct voltage- so i guess they (NAPA or whoever) expect us to just bend the tabs to adjust?

Just did 2 hrs of cultivating, ammeter stayed right at -1 even at high idle. low idle dropped down a couple more. would that suggest the cutout relay also needs adjusting? I thought that was supposed to cut out to prevent discharge.

Bending the tab has been common for several years on some VRs. Care bending is also reason to disconnect Bat when getting serious.
The Cutout depends on more than about five amps discharge to click off. Even then the meter will still show discharge from the ignition system (if coil equipped). The slower it turns, the longer the points are closed in the dist, resulting in higher current draw in the system (not much, but it will show) Try bending the VR relay spring a tiny bit. JimN

Hey Maze... VR’s are supposed to come properly set right out of the box! (Adjusting correctly requires instruments/tools/training not commonly available to the average tractor mechanic)

After installing a new regulator you can verify adjustment by placing an accurate DC voltmeter across the battery posts. With the engine running at max idle RPM it should read 7.0 – 7.5 volts. Less than 7 volts means the VR is out of adjustment.

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You can reset regulator voltage but it’s a fussy adjustment: Again place an accurate DC voltmeter across the battery and run the engine at governed RPM. If voltage is not between 7.0 and 7.5 volts VERY CAREFULLY bend the spring anchor on the voltage regulator relay - the relay whose contacts are held SHUT by spring pressure.

Increasing spring tension increases voltage. But the adjustment is quite sensitive - doesn’t take much change in tension to make a significant change in voltage. Also after making any change put the cover back on and read the voltmeter again – voltage frequently changes when the VR cover is in place.

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Regarding the cutout operation, it’s normal for the ammeter to read a couple amps discharge at idle (it’s indicating the current being drawn by the ignition coil). Also it takes a brief current reversal of 3 - 5 amps to “unlatch” the cutout relay when gen voltage drops below battery voltage. You can observe this when you shut down the engine – the ammeter will briefly flick to about -5 amps then swing back to 0 as the engine spins down. This is completely normal.

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One final thought: Your SC isn’t perhaps fitted with an 8 volt battery? (Battery has 4 filler caps). If per chance it is a 6 volt regulator – even properly adjusted and working – will give charging problems exactly as you describe.

ok... latest update. it is a 6V battery. VR is a NAPA # VR-851. On the cutout relay- the "flicker" on shutdown before return to 0 is exactly as i've observed.

i opened up the VR and started the tractor. at mid-high rpms: if i connect a jumper wire between the 2 sides of the regulator relay (not the contact material themselves, but the metal parts), it pegs the ammeter- just like grounding the F terminal. So that tells me that the VR ground is fine. so remove that wire. the regulator relay looks like contacts are closed ie if i push on the relay, i can't feel any movement to close it. the cutout relay is open. if i push it closed manually, it stays, and the ammeter registers about 5-6V discharge. at low idle, if i manually close the cutout relay, it then opens on its own.

So based on how I understand the VR- it looks like maybe the VR relay contacts are resistive, which means the cutout relay doesn't see gen voltage so it doesn't close? but that woudn't explain staying closed at high rpms. i tried polishing the VR contacts a little, didn't help.

i tried running a second wire from FLD to F, that didn't help either. measured resistance of about .4 ohm across the original wire.

I agree - sounds like the VR relay points have very high resistance. Or possibly there's an open circuit (like broken jumper braid?) between the movable VR relay armature and the connecting circuit.

You might try polishing the VR relay contacts again (use an ignition point file or about 200 grit standpaper). Also look for a broken conductor somewhere between the VR relay armature, its fixed contact and the VR field resistor (located under the regulator base).

At this point however I think you'd be money ahead to simply replace the regulator!

Try running a piece of crocus cloth [fine] through the field contacts on your regulator a couple of times in case there is crud or oxidation.