Need help with my beloved Lawnboy.

I have a model 7086 2-cycle Lawnboy, vintage 1979, and it won't start. It has been gradually getting worse, and now it won't start at all.
I've changed the spark plug.
I've tested the on/off switch with an ohmmeter, and it's working properly.
I've checked the exhaust ports, and they seem ok.
I've taken the carb off and opened it up. It looked quite clean, with no crud, and the float moves easily. No apparent problem, but of course I can't tell if the float is still calibrated, but even if it weren't, it seems like the thing would at least start, or try to.
I've removed the ignition module and put it back, moving it as close as possible to the flywheel magnets without actually touching. And I made sure all the connections were good.
I don't have any way to test the ignition module, and I don't know how to test for spark on one of these things. (Is there a gizmo that I can install inline that will show if spark is present?). However, the manual says it's a "breakerless, capacitor/discharge, solid state ignition system". I assume this is a magneto.
Is the ignition module the most likely problem? A local dealer has a replacement module for $66, which seems like an awful lot for a little magneto. Any way to test this one to see if it's good?
In the process of playing with this and checking the exhaust ports, I've concluded that the compression is still pretty good. There's a big difference in ease of turning between having the spark plug in or out. So I think the mower is in fairly good shape. It's old, but hasn't been used a lot.
Any suggestions? Do I need to spring for the module? Is there a cheaper source?
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The check for spark is to pull off the spark plug wire. Unscrew the spark plug, and then put the wire back onto the spark plug. Lay the plug on a metal part of the frame, and pull the start cord.
The cord should pull easier (cause you have no compression). And you should see sparks at the end of the spark plug.
Hints: Control should be in "run" position. And test should be done in the shade, or in dim light. Cause the sparks aren't very bright. Should be done away from the house, on the odd chance there is some gasoline to light up. Don't check for spark if you've just drained the carb, and there is liquid gasoline on the mower deck (DAMHIKT).
Some mower repair places sell a gadget you can use in stead of a spark plug, for this test. But the plug works nicely.
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Christopher A. Young
Do good work.
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