My Satoh S650g hasn't been started in years and it won't start now. It turns over good but not firing up. I am getting very weak spark, you have to look close to see it, and it's yellow/white. I have been trying to test the coil. It's getting battery voltage when key is on. Across the 2 outer terminals measures 2.3 ohms (multimeter set at 200). Center terminal to either outer terminal reads 8.9 ohms (with multimeter set at 20k). So, I'm thinking I'll try a new coil, but am confused what I need. The one on the tractor now says "use only with external resistor" 12v Made in USA and the number 503. I assume this is not the original coil. But I can't see the external resistor anywhere in-line. Should I buy one of the coils that doesn't require external resistor? Could the lack of a resistor with the current coil be causing the starting problem?
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