have new brigg 17.5 HP.Briggs & Stratton 31R907-0006-G1 500cc 17.5 Gross HP Engine . Does not want to turn over to start. Engine turns over to firing point then stops. Too tight to turn over further even with rope.Turn fly wheel little and it turns over to next firing point. After many attempts will fire and runs fine. Have replaced Battery wires, starter etc.to no avail. Also back fires when first trying to start!