I ran out of gas, and added 1/4 of gas into the tank. I tried to start the engine, but engine has failed to start. I pressed my foot into the accelerator fot 5 sec; then slightly released the accelerator, but engine failed to start. I repeated this step 3 times, each time the enigine failed to start. I'm afraid that the engine has flooded. Could that be the problem? Also, what do I need to do about it?