I suppose you could just drive it to the next county and see what happens... If it is racing, pull the air filter and take a peak at the linkage. Maybe something got bent or debris is holding the linkage open.

I'll try that.
As soon as I get home from work. :-(

Is there a happy sounding mower??!!!

Not really, but it usually at least sounds kind of content.

This is where we can use some simlie faces to add on!!!

I used to have a Crapsman mower that laughed
at me when I tried to start it.

Are the RPM's faster than before or is it just louder. If it's just louder then look for a shot muffler. Or something rattling around like the grass bag frame or the engine shroud.

If the RPM's seem higher then you should get it checked out pronto.

ok, I have same symptoms. I got new air filters. It runs ok if I keep the choke closed, but takes off when I let it open.

If its a vibration, check to make sure the blade is not bent or missing a section. an unbalanced blade can make it rattle and roll.

If it is racing you will need to verify that a linkage issue isn't holding the throttle shaft open or that the plate came loose from the throttle shaft inside the carb.