I have a MTD Yard Machine with a 14.5 HP B & S engine model # 287707 0224-01. I have changed the battery, the air filter, and the spark plug, but it won't crank. It will turn over, but won't start. I took the filter off and started it and it spit out a fluid from the air intake. But when I put the air filter back on, it will not start again. HELP!!