Murray B&S 4.0hp Quattro. Air filter is new, good spark, fuel flow is good. I have made a makeshift starter and I cannot get the mower to start. It sounds like it is firing late if at all and I also checked the shear pin. I don't know the history of this mower but I can't get it to turn over and start. Any help or suggestions would be greatly appreciated.

Michael65, May 2013