Went to start it today as I was low on gas, ( I filled it before starting) nothing, no turn over. I suspect the battery is dead and have a jumper charging but what can I check for the sputtering after shut down? I bought it used from a local reseller, so before I call him, I'd like to do some troubleshooting. I use non ethanol gas with no previous issues. Also what is the correct procedure for shutting down? I usually disengage the blade, put it neutral , hold down the brake and turn the key t...