Murray rider - White smoke and hard knocking

[I-75]

My Murray 12 hp riding mower had the classic "hot start" problem which, as of yesterday, has been replaced by a new problem - yard full of white smoke and loud/hard knocking. Only runs for a few seconds. What's going on? I'm not a person of McMansion funds and I need to know what some of the economical options are for repair if possible. Thanks and God bless!

 

[Rivets]

Pull the oil dip stick and check to see if it is over the full mark and smells like gas. If it does, the causevwould be a sticking float needle valve in the carb, allowing the fuel to overflow and end up in the crankcase. Remedy, replace the float needle and seat, plus drain and replace the oil.

 

[I-75]

Well. Had service come take a look at it. Engine blown. Swell. He is going to try to find an engine for it but it's an old B&S line that is apparently not easy to locate.