Small Engines (Lawn Mowers, etc.): lawnmower wont keep going, briggs stratton engine, briggs stratton

Question
I have a Murray 3.5 (briggs & stratton engine) push behind lawnmower that is emitting white smoke and will not run full throttle.  My son said it was doing this last year, but stuck it in garage and forgot about it.

I noticed that when I move the choke back and forth, nothing happens.  I removed the oil filter case that is above it and noticed there is no spring connected to the choke with anyhting else?  I mean it seems like there should be something connected to it in order for it to do something.   can you help?

Answer
Hiya Patrice
Its certain you have a choke related problem.  I suspect the control push-rod that actuates the choke flap on the carburator is broken.  They're simply a wire inside a coiled spring (sometimes covered with plastic) and they stick when they get old.  Look at your carburator.  The first flap you see when you remove the air cleaner is the choke.  There should be a control rod mounted directly to it- no spring, just a wire with a little Z-bend at the end.  This is most likely your problem.  The control rod isn't expensive or very difficult to replace- lemme know what you see!