Small Engines (Lawn Mowers, etc.): Lawn Mower Keeps Cutting Out, float bowl, verticle

Question
We have a fairly new lawn mower (5 years old?) which has always run like a charm.  The last time however, it would start up but then switch off (cut out) as if it wasn't getting the gas.  My husband took off the casing to check the air filter, etc. and they seem fine.  The strange thing is that if he gets it started and then lifts it by the handle so that the back tires are in the air (and it's sitting verticle on the front two tires only) it runs fine.  As soon as he sets it back down, it cuts out.

Any ideas?

Answer
Not sure which engine you have but it sounds like you have a float style carburetor.

Remove the float bowl nut and drain the carburetor.  Make sure the float bowl nut hole(s) are clean.

The are many posts about this topic; check carb cleaning or mower starts but then dies.

Let me know if draining the carb fixes the problem.
Eric