8N 6 Volt Not Charging

Well, I went out to play with the old tractor a little the other day and it fired right up after I charged the battery.

It ran well for a few hours then I started having to keep it idled up to run. After a few hours of playing I shut it down and it would not spin over to start back up. After a little sitting, it cranked and continued to run poorly. I finally parked it (getting dark) and went out yesterday to play some more. Ran fine for a while and then started having to idle it up. Same thing today and for giggles I checked the battery voltage and the darn thing don't seem to be charging. Apparently I have just been running off battery power for 3 days

So I break out the books and meter and I definitely ain't charging. One thing I thought was odd was I got a spark at the battery cable when I put the negative back on today. Yes this still has positive ground.

I know that I can ground the field and apply 6 volts to the arm to make it tun as a motor to check the generator. Most I've seen had a F and A stamped in the case but I can not find it on this one. Which is which?

As it sits now, the generator is on the opposite side of the engine than the starter. The wire on the top post closest to the engine is actually UNDER the post grounding itself out and the nuts on the post are seized by years of rust. The wire next to it appears to be ok and the wire on the back appears to be ok. If I attach my meter to ground I do not get any voltage at any of these wires. There is continuity on each of these wires with the other end at the regulator. If I attach my meter to the battery with the tractor running, I only read battery voltage (6.2v-6.4v ish).

I've got a new wire harness but have not installed it. My tractor was rewired at some point since 1949 and I'm having issues figuring out which end of the new harness goes towards the front of the tractor. It does not appear to even be close to what I currently have. I also do not currently have an ammeter installed on my tractor.

Anyways, what's a good start to troubleshooting my generator not generating issues? Pics would be more than helpful.

Yep, not charging but don't panic. Your ammeter should show a charge or discharge. Whenever the battery is disconnected, then reconnected, you need to polarize the generator -have you done that? It sounds like you have an early 8N with a front mount distributor and the generator on the right side. It should have three wires going to it. One on the back end plate -big yellow sucker if original - goes to VR ARM post, then two on top of barrel. One is the FLD and the other is GRNd. Email me and I can direct you to a site with more helpful info...

Tim Daley(MI)

Why would you need to repolarize it if you unhooked the battery? It is not hooked up to the generator anyway. Only while charging.

Teddy........it NEVER hurts to re-polarize when you re-connect yer battery. Many neubie shadetree mechanics are used to their 12V Belchfire-V8's and negative ground alternators so they re-connect their 6-volt tractor as negative ground. It don't hurt to re-polarize, yer genny won't mind and nether will yer battery. Just "arc-spark" the side-by-side BAT & ARM terminals together, engine OFF. Me? I use a wide blade stubby screwdriver. You can use bailin'warr iff'n you want. You can re-polarize as many times as it takes to feel warm'n'fuzzy ...er... charged ........Dell

armature is the big stud ont he back of the genny.. field is the INSULATED stud on the bbl.. there may be an UNINSULATED stud next to it. ground obviously.

if you get a spark with key okk, when disconencting bat.. you have a draw somewhere.. check yer wireing.

Yeah, I've gotta figure out what caused that spark when I connected the battery cable. It can't be much.

I jumped the BAT and ARM on the regulator for a second or two and also ran a jumper from the negative of the battery to the armature of the generator for a couple of seconds.

Fired it up and put the meter on the battery. It bounced around from 6.3v-7.2v, so I reckon I'm generating.

Tractor ran much better today for about 6 hours. We will be busy all day tomorrow, so I'll play with that new wire harness later in the week.

Only problem today was the left side of the scrape blade kept jumping out of the quick connect on the 3 point hitch. Always the left side and happened multiple times for some reason. I've ran that same blade several times before without any problems. Sounds like another project for me.

Thanks .