Small Engines (Lawn Mowers, etc.): Craftsman mower smelling like gas, craftsman lt1000, lawnmower engines

Question
Please forgive me for my lack of knowledge about this topic, but I am just wondering if I need to hire a professional to service/troubleshoot my riding mower.  I have a Craftsman LT1000, bought used.  After mowing it smells like gas so bad that it will smell up our house when it's parked in the attached garage.  My husband tells me that it has to do with where the throttle is positioned when it's turned off, and I must say that it does better when he turns it off than when I do.  It also usually blows smoke/black stuff/and liquid as a "spray" out the front when we start it, and it does seem to struggle to start up.  Does any of this make sense and give enough clues to give a possible idea of a diagnosis?  Is the gas smell completely not normal...if not, then I plan to seek a professional's help since we apparently know near nothing.  Thanks in advance!

Answer
It sounds like it may be running too rich or even have a gas leak.  I'd have it looked out even if it turns out to be nothing.  Obviously a gas leak isn't something you need in the garage.  If it's running too rich, this will cause all sorts of trouble with the engine.

It may help a little to throttle it down to a slow idle for a few seconds before shutting it off.  But most lawnmower engines don't use accelerator pumps and won't flow fuel when the engine is shut off unless something is wrong.  So there shouldn't be much of an excess of fuel even if you do leave the throttle in the full speed position.

If you're not used to having a rider, it could also just be that you're not used to the smell.  But just to be on the safe side, having it checked out would be a good idea I think.  Thanks, PK.