Weak to no spark

4hp B&S very old but ran perfect. Cover came off over the winter so it was exposed to the elements until I recently saw. Wouldn't start. No spark. Cleaned everything up and still no spark. Bought electronic ignition. Still no spark
Bought magneto and week spark initially and then quickly no spark.not sure if hooked up correctly. No diagram and zero help from where I bought it or B&S

Yes. Thanks for the reply. Even tried.015 and .020 just out of frustration and 2 new plugs and sanding magnet part if flywheel.

Ok, you need the air gap set to  .010", nothing more..
 
That lil wire to the magneto terminal is the "kill spark" (when grounded) wire.
For now, disconnect the wire from the coil...
 
Check the gap at the plug, should be .030".  Try another known good spark plug as well.
 
Some coils can be put on backwards.  The coil, kill tab is usually closest to the block.
The coil may have something like "up" or "towards the block" as well on the coil..
 
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