Wiring Question
 

I have been trying to get the charging system to work on my 149. Replaced the V/R after doing the S/G test found here and decided to replace the the V/R from a source mentioned here (DB Electrical I think it was). Anyway I get the new V/R on and still get nothing showing on the ammeter, engine sounds like it’s loading a little after it cranks but don’t want to run it too long if somethings not right.

Lots of information on here about these issues and I feel like I have read it all and still no luck.

Out of ideas I thought I would try to polarize the V/R just for the heck of it. When I jumped between the Bat and Gen terminals the engine started to turn over. Nothing I have read says that’s supposed to happen. Would that indicate I have a wiring issue somewhere?

I removed, disassembled and cleaned the S/G, removed and cleaned all the grounds and other odds and ends but nothing else electrical.

I have ohmed the three wires from the V/R as some suggested and the Bat is getting 12v with key off. Only other thing odd is with engine running my voltmeter is all over the place when I put it on the battery. With the engine off it’s a steady 12.5 or so volts.

Any ideas would be appreciated before I rip into the wire harness.

Jumping between the bat and gen terminal will crank the starter.

Did you try grounding the field coil and measuring voltage at the starter/generator with the engine running?

I am confused. Do you have a charging, starting, and/or both issue(s)..??

:Huh:

Oh man.. I would not suggest you rip into anything just yet. Need to slow things down and start over. By start over i mean, put the old VR back in and troubleshoot this thing from the beginning.

Yes. But for what ever reason with the engine running I can’t get a solid reading. Volt meter just dances, roughly 14-.5 volts.

Also the ammeter doesn’t move when I do this. Engine does load up.

Just charging. It cranks fine but the gauge stays on 0.

The rubber mounts have rotted and the old one will not mount to the fender, does that effect its operation? Also pretty sure it’s sat full of water by the looks of the inside. As far as gauge reading, volt meter and operation of the tractor I can’t tell any difference between the old and new V/R.

I think I have read here that some aftermarket VR's are not wired the same as original. Have you verified that the wires are connected to appropriate terminals?

If they are connected correctly the next thing to so would be to GROUND the F terminal temporarily with the engine running. Check voltage. If the voltage rises with power on the F terminal then the VR is bad or not connected properly.

It works the opposite of that, coop. The voltage regulator grounds the F coil to increase the output of the generator.

Voltage might bounce around a lot if you’ve got a dinked up starter/generator though. Could be that you’re not getting current out of some of the windings so as the commutator rotates past the brushes you get some sections that are good and some that aren’t. An o scope would show that but probably not a simple multimeter. Also I would think that starting might be rough if that was the case.

If it’s putting out voltage even part of the time, I think it should probably charge though. Have you measured the output voltage at the bat terminal with the engine running?

lol.. your right.. still half asleep here.. my apologies

meant to say ground the terminal

Update:
I verified the wires were good from front to back against the diagram in the book.

Performed bench test of S/G with belt off, A and F wires unhooked, spun it up with a battery and jumper cables and it slowed down really fast with juice to the F terminal. Supposed to indicate it’s good as I understand it.

S/G spins and starts the tractor very well. Could use some new brushes though.

Removed the cover from the V/R and noticed the following: with engine running wide open bottom point is sparking and appears to be bouncing. Top point begins open but about the time the engine reaches max rpm it closes. If the F terminal is grounded bottom point opens and stops sparking, top doesn’t change. When the engine is shut off about the time it stops spinning the top point opens.

Needless to say gauge doesn’t move, sits straight up and down.

Someone asked what voltage reading was at BAT with engine running, appears to be 12.5. I had to hook my MM up then start engine to get this reading. If I try after engine is running I don’t get anything.

Voltage at battery is still all over the place.

I should point out that I am using the cheapest MM good ole Harbor Freight carries. I beginning to wonder if that’s my problem.

After several starts battery is still showing 12.5 but it was fresh off the charger.

If someone can tell me if that above mentioned point behavior is normal on the V/R I would appreciate it.

I will probably replace the ammeter if nothing else. My main concern is that the new V/R and the S/G do not get damaged. I would think if they were it would have happened by now.

The VR is bad or wired incorrectly.

On the voltage regulator:
the terminals should be identified either stamped or printed.
Batt. goes to battery, and sometimes passes through the ignition switch
and/or the amp meter depending on your wiring diagram.
"F" (field) goes to the small terminal marked "F" on the Starter/Gen
Gen. goes to large terminal on the S/G.
The Regulator needs a good ground or it will not function,
most are rubber mounted so they usually have a braided ground strap that attaches to the reg body and the mounting bolt lug.
Do not go by where the regulator terminals are located, go by what they are labeled as.
Different manufactures put the terminals in various order.
Not all are created the same.
A good,fully charged battery will read 12.65 Volts.
Does your amp gauge show discharge when the key or lights are on? it should.
Is it even connected?? are there any fuses in the system? are they good & making good connection?
if your multi meter on" DC" volts when checking?
Those harbor fright meters although cheap, usually work ok but can go bad.
Sometimes they give them away with a purchase. so you can't expect high quality.
With the engine running at fast speed your meter @ the battery, should indicate somewhere in the vicinity of 14 volts and if the regulator is working to control the output, you will see a little fluctuation in the voltage.

Wiring is correct. I went by what the terminals are marked and physically traced each wire.

Only fuse is inline for headlights.

Amp gauge doesn’t move period. Yes it is connected per diagram.

Only things your other comments bring to mind are that V/R is ground to the negative battery terminal, because that’s how it was when I got the tractor. And the Gen wite goes to the lug on the starter solenoid which in turn goes to the big or A terminal on S/G.

Thanks for the input.

Possibly the amp gauge is bad and open--no contact through it.
Have you checked the terminals on it for poor contact?
If it is open (check it with your meter) then it is possible that is the problem.
(Take the wires off to check it.)
Is your battery charging, or does the battery have to be charged with a battery charger every so often?

Honestly I haven’t ran the thing long enough for the battery to show much drain other than repeated starts. Before I dove off into all of this something drained the battery once so I have been unhooking positive cable if it sits. Also I rotate a battery minder between everything I have that has a battery.

I have cleaned the terminals already.

I don’t remember putting a meter to it but I have stuck a test light on each side and it lit on both.

Now that you mention it, is it odd that the amp gauge doesn’t show a discharge? Even while starting.

I’m going to move the ground wire to the fender and check/bypass amp gauge and see where what happens.

Does the v/r have a braided ground wire going to the mounting tab?

Sparks are good, means it is working, just remove and connect the two wires at the amp gauge together, then check the battery.

I don’t think so but will check.

Thank you for clarifying the sparks, wasn’t sure if that was good or bad.

That’s exactly what I was planning on doing, from what I have read I was under the impression that the amp gauge could be bad but not interfere with anything else you just wouldn’t get a reading from it.

Depends how the amp gauge is wired but the power has to pass through it either charging or discharging or it wouldn't indicate anything.
Yes i know about induction type meters where just a wire passes through a metal loop.
You will find the problem, they ain't rocket science.:beerchug:
when checking the amp meter for continuity, remove the wires from both terminals.
you should see zero resistance on yer meter.

Well. I still think I new a new MM.

Amp gauge doesn’t make my MM do anything. So just bypassed it and put all the wires on one post.

Also I took the ground wire for the V/R off the battery and put it on the top bolt that holds the VR to the fender. Also tried an additional ground to the post as well as the body of the VR. If there was any change it was just that my meter didn’t fluctuate as bad. At one point it actually showed 14.5 at the battery but when I took the leads off the reading stayed and the meter acted like it was stuck.

What could I do so that the top point of the VR moves? Like I said in earlier post it is open with everything off but once the engine is running it closes and stays that way until engine is off. If I ground the F terminal the bottom opens but nothing I have done gets any action from the top one.

Only thing I forgot to try was if engine will stay running with positive lead unhooked. As of last night it wouldn’t.

Just to close this one out and post the solution for someone in the future.

I finally figured out what my issue was, broken connection on one leg of the top contact point. After watching this video, https://m.youtube.com/watch?v=5ngzb_Avfkk, I was better able to understand what is supposed to happen and ohm out each connection.

A quick remelt and attach and we are showing charge on the gauge, will run without the battery.

My VM is still jumping around but I have heard the Harbor Freight ones will do that. About 16 on the S/G and 14 at the battery.

50 years ago my boss in the 2-way radio dept. where I worked, said you could fix half the problems just by using your eyes. I've found this true most of the time.

Voltage Reg.
 

Are you talking about the top contact point on the new voltage regulator? Wouldn't the new voltage regulator have cured it if the old one was bad? I am lost here and probably don't understand what is going on. Glad you got it fixed and have a great day.
Bob

The bad solder joint was on the new VR, the contact was opening and closing like it should but when it closed it was not doing anything.