SA Coil

1. 3 cell battery is 6 volt (each cap is one cell)

2. Farmall SA is positive + ground, not negative - ground

3. Coil should be hooked up - lead coming from ignition system and + hooked to the distributor.

4. I have found that one of the reason coils heat up and or fail is, that the oil has leaked out over the coarse of years. The coil is filled with transformer oil,which acts as a coolant.

Keith & Shawn

First, I agree with Bob M, now knowing the tractor is 6 volts makes it much harder to see why a 6 volt coil would get so hot????? Unless its plain old BAD orrrrr rrrr they made some 6 volt coils for different then IHC applications which may be much lower resistance then the more typical 1.2 to 1.5 or so ohms like IHC used. Sooooo get an ohmmeter and measure the coils primary winding resistance between its lil + and terminals n see what the heck it actually is...

If the coil were continually drawing current like if the ignition switch were left on it gets hotter.

Youre correct, if youre at Neg ground then the coils - wires to the distributor.

I think myself n others well described things that cause the plugs to soot up below. Id still run the hottest non resistor plugs available and use wire core plug wires and get the engine temp up and lean the carb n check for choke or air inlet restrictions n see what happens.

Let us know

John T

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You CERTAIN your SA is on 6 volts? The only way I know a coil can overheat is when a 6 volt coil is used on a 12 volt system without a ballast resistor in series.

Unless there's a partial short or something inside the coil it's virtually impossible to overheat a 6 volt coil on 6 volts!

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Before you begin diagnosing the engine "woofing", dark exhaust, etc. install a fresh set of plugs! The soot on the plugs in there now now will cause all manner of misfiring and other odd behavior. Suggest also replacing them with the hotter Champion D-21 - or the AC or Autolite equivalents. (The D-16 would be OK if the tractor is in good tune and is worked hard. But when the engine is only lightly loaded - and with the lousy quality gas we get now - the D-16 has a tendency to carbon foul very quickly.)

Good luck and keep us posted!

In reality, it doesn't matter which ground it is. Negative ground is better because everything that has a battery in it these days is negative ground. Less confusion when it comes time to jump start. There is no other technical advantage to one over the other... It was just how they did things in those days.

Maybe you have your coil wired up backwards?