I have a Murray309029X2 with a 10hp Briggs and Stratton engine that won't start. This was "freebie" from my father in law after it just shut off on him while mowing one day and was too lazy to try and fix it. I changed the gas, recharged the battery, changed the plug and tried a little ether in the intake. When I try to turn it on the engine spin and spins but won't turn over and start. I can't tell what's going on... any help out there?