I believe you're right Phil. It seems like what the oils are suspended in is what's causing our trouble.
Today, I received an order of Singer Lube and it's the wrong stuff.
I received a blue tube - probably updated to look more modern but basically the same stuff Joe has.
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I popped some in the toaster oven to see what it would do.
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Crap.
That residue is bad and potentially the fact that it's spreading faster than the original is bad too. It seems to me it may be less stable and the residue will clog the wicks.
I'm going to spend the next little bit on the phone with a couple of electric motor repair shops and see what they say.