205cc 800 series ,want fire ,its getting gas and i put in a new plug ,it started and ran fine the last time i used it ,only been used maybe 15 hours what do you think it could be

If it's not starting with starter fluid, and it only has 15 hours run time, I'd say you may an ignition problem - no spark. Have you tested for spark? First, try a new plug (sometimes you get a factory reject). If it's a NO GO, try this: disconnect the spark plug wire at the plug. take a small stick, a chop stick or Popsicle stick and tape the stick to the plug wire with the end of the stick extending about 2 inches beyond the connector. Lay this end of the stick along side the plugs insulator just below the plugs electrode, leaving 1/4" gap between the plug and the electrode. Now pull he engine over. If you don't get a hot spark jumping the 1/4" gap between the wire and electrode you've got a bad or mis-adjusted ignition module.

If it start with a little induce into the carburetor throat then check the fuel bowl bolt is clear as it is also the main jet for the carburetor. They tend to clog when the engine is left sitting long periods of time.