Super C light- Update...

I had alot of comments on last post so I will tell you what happened Went to town and bought a pigtail with a 194 bulb; cut white wire between 2-wire plug on alternator and light on dash and installed pigtail with bulb; started tractor and have same problem; takes full throttle to make light go out and amp gauge charge. Thanks.

What diameter pulley is on the alt.? On my8n ford I used a 2 5/8 " pulley i bored to the correct bore and it works great. Light goes out at a little above idle.

Get a smaller pulley. Make sure the v width is the same as the crank and fan pulleys so the belt doesn't ride high and further increase the diameter.

Light bulb goes in the #1!!!! wire not the #2. #2 is the sense wire which tells the V.R. the condition of the battery so if not wired correctly you can be why it is not working since you don't have it wired correctly

It is on No 1 wire in the plug.

Your post says it is on the #2 lead

The alternator on my second 400 needs to be rev ed up to excite the charging system. After the light goes out, it is charging. Why do you think that it is a problem that has to be fixed? To fix it, get a smaller pulley for the alternator.

I don't understand all these problems with alternators and having them charge. We have one on an MD they only turn about 1650 at full speed. It charges fine with the pulley that came on it. Been there for over 20 years. We have a switch for the excitation since it has a mag on it.

Was the new alternator supposed to have been set up specifically for tractor use? From the beginning you said the light worked and it charged at higher rpms. During the course of the thread you revealed you have an ammeter as well and it showed 15 amps when the light went out. At that point the ammeter confirmed it was charging and that the light was working properly; in my thoughts. There was no need to change or add to your "idiot" light. While a three wire should start charging at a lower rpm, it apparently is not.

You don't seem to want to listen to the suggestions of installing a smaller diameter pulley. What is the diameter on the pulley you have on the alternator now? Does the belt width match the width of the crank and fan/water pump pulleys? Just because it came on the alternator doesn't mean it is correct for your application. Are you running the right width belt for the tractor or a narrower one to fit a narrow pulley? I have changed the pulleys on my conversions to get the right belt width and when doing that go to a smaller diameter for better charging lick in at lower rpms. Just my thoughts, others will differ. Hope you find the right fix.

No I will listen to a smaller pulley...just havent got there yet; I will measure it this morning....thanks!

Reread my post 2 times OLD...Im not seeing it.

It has a 2 5/8" by 3/8 pulley but a 1/2" belt on tractor; so it is an automotive set up; my parts store does not have a
smaller pulley but does have the same size pulley in a 1/2" so I will pick this up today and change it out and hope it works
better; if not it will be fine the way it is! Thanks for the help!

"cut white wire between 2-wire plug on alternator and light on dash and installed pigtail with bulb;"

Did you remove or bypass the light on the dash? If not do so.

The fact that you can rev the engine and get it to charge indicates to me that it may be a one wire alternator. Some of them will excite quicker with lamp, resistor, or diode, but the one wire regulator may may work better with resistor or diode than with a lamp.

If it were mine I would try a diode in place of the lamp.

Sorry about the not listening comment. I have been through the same thing on one I used a diode to excite and a smaller pulley made it show charging sooner on the ammeter. You said your light was working but you had to throttle up to start charging. Then you posted you have an ammeter and it showed charge when the light went out. So that side of things is working. I use a small pulley, on any I convert now. I have gone to using voltmeters instead of ammeters as well.

Make sure the your belt width fills the crank pulley, you want it riding high there to keep the feet per minute up, belt flush or slightly down at the alternator. Hope it works out for you this time.

No I bought this alternator to replace the one that was on it. It is automotive set up. I WANT the light on the dash- thats why I bought a new one and put it on- Im restoring this tractor. So last night I changed the pulley on this alternator- went from a 3/8" to a 1/2" pulley- same diameter...seems to have helped as light goes out about half/throttle...thanks foe the helps guys Happy Holidays !