Lawn mower engine runs rough and puts out white smoke

Hi Jeremy:
Sounds like there is still diesel in the fuel system.
There will be a plug on the bottom of the carb.
If you unscrew it and allow it to drain, it will flush the carb.
I'd suggest changing the fuel in the tank again.
You may also need to change the spark plug.
You won't have damaged the engine.
Cheers.

The bang noise. Check timing. The key holding flywheel in place.

it might not have been over filled with oil i have seen many needle valves not seating in the carb the gas over fills the carb and drains into the crank case thinning out the oil and if not caught in time i scores the cylinder wall

probably the valves have unseated the hotter it run the worser it get warranty defect take to dealer tell what it doing tell him you think its un seated valves and cover under warranty

white smoke is more than likely a water issue. Oil usually has a bluish tinge to it but is some cases, it could be white. Drain the gas a fill with fresh to try and eliminate the possibility of water in the gas. Watch the oil level to see if it changes after using the mower. it may take a few times but if it is burning oil, the spark plug will look "wet" and oil soaked, with possible black soot type build up.

Check the gas you put in, it sounds like it had water in it.

adjust the carby. also u might want to replace the diaphragm in the carby. might work wonders

That is a Briggs & Stratton engine and given its age, I would say it is time to overhaul or replace the carburetor. Over time the float needle and seat become worn and inoperable which is why you are getting fuel in your crankcase. If you are not familiar or comfortable with working on these things, this is a job better left to a professional. There are too many things that can (AND WILL) go wrong in trying to do it yourself. Just scan through some of the questions on here and see how many others have taken theirs apart and can't remember how to put it back correctly!

does it turn over slow or fast if it turns slowly thats the problem so it could be battery or starter they have to have a good amount of rpms to burn fuel right when starting if not it floods out the engine with gas hope this helps thanks wade

for wiring diagram go to
http://www.tulsaenginewarehouse.com/drawings/allwiring.pdf