Small Engines (Lawn Mowers, etc.): tiller-no spark, troybilt tiller, starter fluid

Question
I have a TroyBilt tiller with a Tecumseh engine.  I can't get it to turn over.  If I spray a little starting fluid into the carb, it fires just briefly.  I removed the spark plug and held it next to the block to check for spark and got none.  Is this a carb problem or spark?  I don't know if I'm checking for spark correctly.
thank you

Answer
 Hello Ethan:

 Wrap a Piece of Safety Wire Around the Threads of the Plug. Attach the Other End of the Wire to the Bolt Above the Plug Hole. Do you have Fire? You Stated it Will Run if You Spray Starter Fluid Into the Carburator. From This Statement, I Suggest you Clean and Rebuild the Carburator. Hope this Helps. Let me know what Happens, Please.

 Good Luck

 Respectfully

 John