I have a Craftsman push power with a 149cc Kohler XT6 Courage engine.  It's just over 2 years old (just out of warranty) and it won't start.  I replaced the spark plug, and if I take the plug out and put a bit of gas in there, it will run brielfy and then die, so obviously to me it's not getting gas.  What are my next steps?  Replace fuel filter maybe?