On Thursday, April 9, 2015 at 2:17:15 PM UTC-4, wrote:
I have a troy bilt horse xp with a kohler 22hp engine sv620 it will only start if i use starter fluid. i left old gas on the tank so i drained the tank and sprayed it out with ether and bleed the fuel lines to the carb i also removed the diaphram and sprayed it out with ether.

From the symptoms it's likely leaving gas in it fouled the
carb. The solution is to remove the carb, disassemble it,
thoroughly clean it with carb cleaner/compressed air
and put it back together.
Thoroughly cleaning it may involve removing welch plugs, if it
has them, to get access. There are rebuild kits sold online,
Ebay, etc for ~$10 that include new needle valves, gasket, etc.
Depending on the condition of the gasket between intake and carb,
you may need to pick one of those up, they are sold separately.