how hot is stock coil?

The voltage at which a plug fires (among other things) is a function of the medium (fuel and compression) in which it fires PLUS the plug gap distance i.e. why a stock coil could fire at same voltage as a HV coil.

Nowwwww that being said, to gain much in performance you would use a high energy high voltage coil and couple it up with an electronic ignition switch (to replace points) and then run that wider plug gap you mentioned AND END UP WITH A FATTER HOTTER SPARK ACROSS A WIDER GAP (more energy discharge) to better ignite the fuel

If you only replace the coil and run a wider gap and depending on the coils specs you can indeed force it to fire at a higher voltage but at the expense of possible premature point burn up if youre exceeding the normal current..... .

I agree with my buddys, use hotter plugs,,,,, get n keep the temp up to 180 and over,,,,, dont run the carb over rich,,,,, ,give her 2 aspirins n call us Monday at the office

John T

If cleaning or replacing plugs temporarily cures the misfire, the problem is not likely the coil. In fact installing a “high voltage” coil may even make it worse.

Suggest rather you look at the following:

Spark plugs’ heat range is too cold. Switch to plugs 1 – 2 heat ranges hotter than what the manual suggests. (Note: This is a common problem when you combine extended operation under light load - the “yard work” you mention - with the poor quality gasoline we’re stuck with today.)

Carburetor is set too rich. If you see any trace of black in the exhaust – especially at idle - it’s too rich!

If you use the choke to start the cold engine, get the choke opened and the engine under load as quick as possible. (Excessive choking on a cold engine fouls plugs VERY quickly…)

Make sure the engine’s thermostat is present and working. A cold engine lightly loaded tends to foul plugs.