short question - 8N dies - cooks battery

Subject: 1951 8N, 12V Conversion, 6V Coil.

Symptoms: (1) If I don't disconnect the ground cable from the battery after every use, battery goes stone dead after a couple of days. Is this normal?
(2) Tractor runs good for about 3 hours then dies. Its acts like it's fuel related, but everything checks out OK. Not flooded, good flow, clean fuel. Will restart after a few minutes - but quickly dies again. Wait a day and it's good for 3 more hours.
(3) The battery is boiling over. Ampmeter constantly shows +20 when running. Battery starts leaking acid within a few minutes.

What I've tried so far:
1) Self Regulating Alternater couldn't be checked at local parts store, because it needs to be "excited" to charge. Drove 30 miles to a "Starter Shop", where they told me it was OK, but I'm still skeptical and afraid to put a new battery in at this point.
2) Took the battery to a local garage where they tested it for a short. It's OK although on the low end of "GOOD" (It's been "cooked" three or four times).
Whats next:
I'll be checking the wiring today for shorts. Is it time for a new coil? If so, 6V or 12V?
Any help will be greatly appreciated.

Harry

A.) The Alt P2 connection MUST be connected via a Jumper to the Alt BAT (output) connector. This is the voltage Sense required for regulation.

B.) The Alt P1 connection (excite) should be connected, via a diode, to the switched side of the ignition switch. When the Key is off there is no voltage to the Alt excite

I would get your Alt working first and then see what part of the ignition (coil etc) is damaged.

Hope this Helps,

You have an "external" regulator.... The 10-S1 that most use in 12v Conversions has an internal regulator and the P1,P2 connections.

I would replace your External Regulator

Sorry for confusion.

When tractor dies after 3 hours run time - immediately try opening the gas cap (be careful not to get gas on the hot motor etc) If you relieve a vaccuum in the tank that could be your run time problem. Get a properly vented gas cap.

"Self Regulating Alternater" - is this the typical GM 3 wire alt? If so, it sounds like it's 'self regulating' system is faulty. Depending upon battery condition, the amp guage should show a fairly high reading after starting, and that should steadily decline until it reaches almost zero.

If your three hour run time problem isn't solved by solving the alt output problem you might try the usual suspects like key switch and coil. Also with a 12 volt conversion you want to make sure you have the right resistance in line to the 6 volt coil. If you replace the coil, I'd get a 12 volt from Don b. You will then need a different resistor to the coil.

Hope this helps as a starting point.

Mountainman...CA

The alt looks to be from a standard "8N-12V Kit" as the alt base and adjusting brackets still have paper 8N stickers on them. The alt is marked "DELCO REM" or "DELCO REMY". There are 2 terminals - BAT and GRD and a 2-wire plug plugged into a socket labeled "L F". All four wires BAT GRD L and F run to a small self regulator mounted on the alt, so it appears to be totally self contained. Of course a wire runs from the BAT terminal to the battery via the ampmeter.
I can't tell if the wiring harnass is home-made or just ancient, but on unwrapping some of the electrical tape just at the alt, I found 2 cut wires (from the old 6V generator I assume). I may call DonB on Tuesday to see if this is one of his kits and if it's installed correctly.
Thanks for your help,
Harry

I haven't any real hard knowledge about your external block of "sumptin". I have heard of a 1-wire kit that makes the alternator output at the low rpms typical of tractor engines. Have also heard of the low rpms charge kit refered to as a marine kit. But I don't know for certain.

I do know that there is a 2-terminal plug wire pigtail available that you can use instead of individual blade type connectors.

I really don't know what "L" or "F" mean. L for light, as idiot light? or is it a badly printed 1??? F as a badly printed B for battery? or badly printed S for sense? or badly printed 2???..... gack..... ..

Bottom line, from your descriptions: boiling battery is caused by overcharging. Overcharging is caused by bad voltage regulator. Replace your alternator with a good Delco SI-10, they're cheap which is one reason they are popular.

From your descriptions: 3 hours of running and then quiting and overnight "miracle cure" is symtomatic of a bad ignition coil that you cannot test except by replacement.

HTH..... ...Dell

It used to be I had to excite the alternator by getting high rpms and then the Ammeter would should charging. Soon after the conversion this stopped working and the batt started to boil.

I used to short the two spade connectors off alternator and it would work alright, now nothin.

You wrote..... ."It used to be I had to excite the alternator by getting high rpms and then the Ammeter would should charging. Soon after the conversion this stopped working and the batt started to boil.

I used to short the two spade connectors off alternator and it would work alright, now nothin"

YOU HAVE KILLED YOUR BUILT IN TRANSISTORIZED VOLTAGE REGULATOR BY STUPIDITY. AND PROBABLY YOUR BATTERY TOO.

Once you get your 12 volt alternator's built-in V/R fixed, here is what you do.

1) connect your "P-2" voltage sense blade terminal by a short wire to the alternator's battery output stud.

2) connect your "P-1" excite blade terminal thru an "idiot light" scheme using a clearance lamp to your ignition switch on terminal.

3) connect your alternator's battery charge output stud to your battery positive terminal, usually the big battery stud on the starter solenoid.

Respectfully..... .....Dell