Hi Mozz,
I think your model is one of the newer versions from 2009-2010
So I just have to ask, I am certain it has a safety handle that has an engine clutch/ignition ground to stop the blade quickly as possible when the operator leaves the handle area.
When you are checking the spark, do you have that handle held in the run position?
I just find it terribly hard to be able to run the mower and hold all the safety features at the same time. The lawyers and congress has it so you can't pull the starter cord and be anywhere near the engine, let alone check the spark by yourself. It is set up like a dead man switch, so If you are not by the handle well at least a good 5 feet from the blade, the thing is designed not to run.
I would not dare to recommend that anyone try to tie the handle shut with a strip of cloth or light rope as I may get it trouble with the mower police or bring about a lawsuit. That and of course I would not want anyone to get hurt.
That is what I wouldn't do...
You got it to pop and run for a short time, so you had something. I just bought a new carburetor for my 10685 on ebay for about $20 The parts to rebuild my carb were that much to do it myself. My 10685 has a different motor on it. (Techumseh)