Export thread

i just picked up a pretty clean troy bilt tb320 for free because it wouldn't start. I pulled the very dirty air filter and the spark plug and confirmed it had spark. after reinstalling plug I sprayed starting fluid into the carbs throat and tried to start. it would spit a couple times and puff smoke through the carb and muffler, nothing happened. it would also make a noise similar to knocking with the plug in, but without the plug there was no noise at all. the guy i got it from said it ran fine last year and when he tried starting it up for the season it didn't run. im considering a lot of possibilities but i need to narrow down the root cause before I start buying parts to fix.

Since some people don't always tell the truth and it being a push mower, i would check the flywheel key. Seems to be in ignition issue or ignition timing issue.
you'll have to remove the top engine decorative cover, and remove the flywheel nut. You can block the blade with a chunk of wood to keep the engine from spinning when you loosen the nut.
the key should maker a perfect square in it's slot. you'll see it.

Here's an example of a sheared key.