6 volt-8volt-12volt confusion

If I was gonna convert and wanted her to crank fast for good winter starts, Im not a fan of 8 volt systems and would go ahead and convert it to 12 and be done with it.

Many old trctors, especially the 6 volt, were originally Pos ground, but Im unfamiliar with Fergusons??? HOWEVER they can work either way if the VR is compatible and you polarize the genny, so I would stay at neg ground.

If it was pos and changed to negative ground, any ammeter leads would needed swapped and the coil rewired + from switch and - to distributor.

At 12 volts you need EITHER a 6 volt coil with a series voltage dropping (12 to 6) external ballast resistor (ahead of coil n after switch) or a full 12 volt rated coil. Otherwise the coil overheats n the points burn up prematurely.

I can help you with a weak spark more later, but until then check the points and replace if badly burned or pitted and check the gap. For now I wonder about the ignition switch (may have burned or resistive contacts) or try to hot wire the coil n see how well she fires??? Your coil (from overvoltage) or condensor may also be weak. When running a 6 volt coil at 8 volts the coils run warm and the points would burn up quicker, so I wouldnt worry aobut the spark till AFTER I converted to 12,,,,, ,,got a new full 12 volt rated coil,,,,, ,,,got new points n condensor. On 6 volt systems I recommend 00 Gauge batteyr n starter n ground cables and a good ground to lessen the voltage drop when cranking which causes a weak spark.

A genny repair shop can convert most exisiting 6 volt gennys to 12 leaving the same case and you would need a new 12 volt VR of course. I have made 6 volt gennys charge at 12 volts simply by replacing the VR to a 12 volt but Im not saying thats the correct engineeirgn way to do things.

Gotta run, John T, retired electrical engineer

If you already need a battery and generator rebuild anyway... it may be worth the expense. Generally speaking, converting to 12V as a means to fix poor spark or starting, is usually an expensive way to compensate for some underlying problem that is keeping the 6V system from working as it is intended. Chances are you can fix your 6V system much cheaper than converting to 12V. There ! ... I'm off my 6V soapbox now. Weak spark on 6V can be caused by bad coil, or using a 12V coil; improper point gap or burned points; bad condenser; dirty connections (big culprit) thru the ignition to coil, to distributor, or to ground; using resistor or cheapo plug wires (copper core is best); running negative ground, or having the coil wired in backwards(it does matter with 6V system).

Your generator output my be a very simple problem. Try this before spending money, polarize your generator with your 6V battery installed with pos. ground... I forget the exact polarizing procedure right now, do a quick search - I'm sure you will find it in here. Then run your engine ~1/2 throttle and connect a lead from the generator F (field) terminal to pos. ground. That will force your generator to full output. Check your generator output, volts and amps. If the output isn't > 6-7 volts, and > ~12amps or so, your genny needs work. If you get good output, then your regulator is causing problems.

George

The Voltage Regulator to 12 volts IS A MUST HAVE, you will have to change any light bulbs to 12 volts.

No, the points are a pure mechanical current switching device and their voltage withstand rating is far above 6 or 12 volts anyway, so they will work as is, no difference or change required. Likewise, any ammeter isnt voltage specific, it measures the current flowing through it and isnt much concerned with the voltage across it, ideally, its a short circuit anyway. The condensor should also be fine as is.

You have to go to a regular battery supply house or maybe a heavy duty truck dealer or a welding supply house or a big tractor dealer to get 0 or 00 Gauge battery cables, the lighter No 4 like autos use drop too much voltage. NOTE if you change to 12 volts its not as critical, but I would still use 0 or 1 Gauge even then although 2 would work.

John T