127 Amp Gauge

[Juicybusa]

127 amp gauge constantly fluctuates in the positive range at anything above idle. I'm not accustomed to seeing this level of needle fluctuation since my O does't have one. Voltage reads 14.5 at the battery fast idle. Gauge? Regulator? Or normal?

[mattoney]

I just got the charging system on my 107 running tonight and have had the exact same issue. It'll bounce all over the charge side for awhile until I slow down to idle. Then it goes all the way to discharge for about a second and then centers out to 0 until I speed it up again.

[Juicybusa]

I think I've narrowed this down to regulator vibration. Don't know if I am missing some dampening rubber on the regulator mounting or not or if possibly the cubs require something unique about their regulators to tolerate the vibration. Any further insight appreciated.

[gophred]

I think you are on the right track. I had that on a 129 I bought which had totally dead battery. The owner started it, but only with a 100 amp charger and the V.R read zero so I was not confident about the charging/regulating. When I got home with a good battery the regulator was flying all over. I put a spare V.R. in and it read much steadier and positive. could be the adjustments letting the vibration open/close things when they should not be?

[Juicybusa]

Originally Posted by gophred

I think you are on the right track. I had that on a 129 I bought which had totally dead battery. The owner started it, but only with a 100 amp charger and the V.R read zero so I was not confident about the charging/regulating. When I got home with a good battery the regulator was flying all over. I put a spare V.R. in and it read much steadier and positive. could be the adjustments letting the vibration open/close things when they should not be?

Totally agree!

[dagenham]

My 127 bounces all over the place from discharge to charge at high idle. I'm not sure if my charging system is working correctly or not. The s/g is fresh and the v/r is supposed to be good, but that is questionable to me.

I am with juicy and the dampening rubbers on the v/r. Is there supposed to be some there or not???

[darkminion_17]

I have had the same issue and changed the amp gauge and it works fine now.
They do go bad.

[mattoney]

I yanked the cover off my voltage regulator and found one set of points seem to be really smooth, the other set seem to be rather pitted. So I'll clean those up and check all the gaps per the 107 service manual I found on here and report back.

[mattoney]

Okay. I'll try to make this one brief so everyone can get a good laugh.

Per some instructions I found on here about testing a s/g, I started the 107 and ran it at full throttle, checking voltage off the Armature pole to ground. I got about 14.2 volts, which was within spec. However when I throttled down to idle, the Amp Gauge would still go all the way to full Discharge for a couple seconds. Sometimes it would act like a switch would throw and the gauge would go to zero, and other times it would stay on D. I decided to pull the cover off the V/R, restart the engine, and found the cutout relay points were sticking when I throttled down. I was losing daylight so I shut everything down and put the cover back on, and that's when the engine started cranking on its own and the magic smoke escaped the V/R.

I had a spare that came off a Case 220 with the same style S/G, so after testing my key switch, solenoid, wiring harness, and a few other things, I plugged in the "new" V/R and everything started up and worked just fine. So I got lucky there.

Had the V/R not burnt up, I was going to do the procedure detailed in the 107 Service Manual regarding filing and gapping the points. I bet that would have fixed it.

Hope this helps anyone with these problems.

[Cubcrazy]

Thanks for the update!