Small Engines (Lawn Mowers, etc.): lawn mower engine problem, hp engine, fuel filter

Question
I have a John Deere push mover 6 1/2 hp engine, I had it tuned up begining of season.  Today it started running fine, but later it became sluggish, only a little power, I checked to make sure it had oil, I put new gas in it today. I gave it a rest, it is still doing same thing, engine starts, but runs very slow.
please help.

Answer
Hiya Terry
Obvious first - put in a new plug and change the air filter.
If it has a fuel filter, replace it.
Next, drop the fuel bowl and check for water.  It won't hardly go through the mower, it just collects in there(it actually is formed from condensation, and can build up gradually)eventually the mower won't run at all.
Lemme know how it runs after these checks!