I have not been able to get a spark on my Tecumseh 12.5hp engine. I have bought 2 new coils (from different suppliers) and still cannot get a spark! Both were matched against the engine type/serial number. The magnets on the flwheel seem to be strong, as when I fit the new coils the magnetism grabs the coil against the magnets on the flyweel and makes it difficult to set the air gap. Not knowing how strong the magnets should be, is it possible to increase the strength of magnets by rubbing a stronger magnet against the ones on the flywheel? Other than that I am at a loss as to what to do next to get a spark! Thanks, Terry

The air gap is set at .010" or you can just use a business card..
 
Did you disconnect any kill wire at the coil and then check?
 
I assume this doesn't have points, correct?

Air gap set at .010, Kill Wire disconnected & No Points. Just magnets on the flwheel that active the coil on each rotation. Thanks, Terry
 

You may need an OEM coil.  Just cause it's new, doesn't mean it's good,
(especially with aftermarket China parts).