Did you figure out why your mag went bad in the first place?
Are you sure it was your mag!
Check your spark-plug boot! That little brass insert that clips onto your plug could of vibrated loose and that would interupt your spark.
Those inserts screw in.if you look in at it you'll see a straight slot machined into it.
There's a spring behind the insert.
What I do is with a straight screw-driver try to screw it in as far as I can,when I'm satisfied it's in as far as it'll go.
I take a syringe with green lock-tite and squirt about a drop or so of it next to the insert and bump the side of the boot till the lock-tite seeps into the threads of the insert and boot.
Also make sure that your spark plug wire isn't so long that it's cocking your boot.Some kits have crappy rubber plug guides"the cap at the end of the boot that the plug slides into"this will put a strain on the insert,and eventuatially the insert will fail.
So if your plug wire is the right length this will help there.Your plug wire can be unscrewed and cut to size.
I also put shrink tubing on the CDI box end of the plug wire this helps keep moisture out of that connection.
Could be your plug is fouled these little engines don't seem to like lots of fuel when starting
I also use electrical silicone/grease on all the connections and shrink tubing after.
I also remove the kill switch from the throttle handle and slide some shrink tubing over the wires right up to where they are soldered to the switch and shrink it to the wires.
Then I reasemble the switch,This acts as a strain releif.
Well,That's a bunch of shots in the dark for yah hope one of them will hit the target your shooting at.Good luck,Kip.