Here are a few ideas, but I don't claim it is any of them.

1) Bad (contaminated) fuel - was this the last gas in the container?

or

2) Debris in the tank got sloshed around and has plugged the screen, hose, or filter

3) Coincidence. I don't like this choice, but it could be a problem unrelated to the fuel system such as an ignition problem.

I would suggest looking in your gas tank and gas can and look to see if you see water or debris at the bottom.

TIP - I like to use the clear hose between the fuel pump and the carburetor to aid trouble shooting this type of problem.

Good luck wheely

Sometimes when you run completely "out of gas" and run the carb bowl dry, a small particle of grit, previously "barred" by the small opening afforded by the needle valve (under "full bowl" conditions).......will make its way into the carb bowl when the bowl begins to empty and the float drops (opening the needle valve wider than when bowl is full) as the fuel level drops. This particle (or particles) of grit might then make their way into the main jet, which can cause lean mix and surging. If the grit gets into a pilot jet, it might also induce some surging BUT the most obvious symptom of a clogged pilot jet would be that the engine will not idle at low RPM. With a clogged pilot jet, you might be able to get the engine to start and run at higher RPM (and it might surge), but when you tried to get it to idle at slow speed, you would reach an RPM (higher than normal idle RPM) where the engine would suddenly begin to stumble and then die like it ran out of gas. You may want to empty the carb fuel bowl (catch the contents in a clear, clean glass or jar so that you can examine what you pour out of the bowl). If you see some slugs of water (water can sometimes clog a pilot jet) you should spray some carb cleaner into all the holes and passages on/in the carb. If you see some gritty looking junk, you might have to disassemble the carb and probe the holes with wire and blow out with compressed air. As njdpo suggested, you may want to "add some dri-gas, or Methanol alcohol to disperse and transport the water out of the carb.

When I run by briggs vanguard out of gas it does the same thing. IMO you still have air trapped in the system the the Erratic problem is the air working it's way through the fuel pump, lines, and the carb. run the sHyT out of it at different throttle setting or throttle excerises and see it that help after a few minutes. Mine usually took about 5 mins to straighten back up and run right.

Sounds like water. I've had to pull my carb bowl off and wash it out with alcohol. An old craftsman push mower wanted that done every spring.

Thanks for all the advice. I am hoping that the problem is either water or an air bubble. I use the machine year round, so the gas is no more then a few weeks old. It is possible that I bought gas with water in it but I not having issues with any other equipment. Also, I am hoping the in-line fuel filter (just changed this spring) would keep grit out of the carb.

Well the problem has persisted till today. I pulled the carb and cleaned it out. Now she runs like a champ!

Might look in the gas tank if your LT it's few years old? if it is cotaminated the problem might reoccur. I take my gas tanks off and clean them out ever 2 to 4 years. Especially if I have excessive trash collecting in the fuel filter. IMO some of that stuff makes it pass the filter and ends up in the carb bowl settles and when you run out of gas is sucks it up into the jets as bunnyman suggested.

***"IMO some of that stuff makes it past the filter and ends up in the carb bowl settles and when you run out of gas is sucks it up into the jets as bunnyman suggested."***
EUREKA!!
Now that right there has a lot of merit. Normally, the fuel bowl stays pretty near full when the engine is running because the fuel can enter the float bowl as fast as the engine can suck it out. For that reason, the float never actually drops very much, and therefore the needle valve only opens just a little bit, and, because the incoming fuel is just "trickling in", no real swirling or stirring up the "dregs" occurs. BUT, if you run the tank and float bowl empty (in a fuel out), and the float drops as far down as it can go, the needle valve is now wide open. Refill the fuel tank and crank the engine. Now, with the float down and the inlet needle valve "wide open", the incoming fuel "stirs and swirls" the tiny bit of fuel that was left in the bowl. Any debris in that bit of fuel will be roiled and sucked into the jets. Some of the debris might be a drop or 2 of water, but some other, more solid junk could be there too. Very good possibility that the sediment plus the "un-usual" rush of fuel could be the keys here.

I had the exact same problem with my GT245 this past year. Three times I took it to the shop because it would run poorly, idle poorly, not develop full power, and sometimes just stop. The first time the Deere shop told me there was water and dirt in the gas, they cleaned the carb, changed the spark plugs and fuel filter and installed a new air filter (the wrong one for the engine, it turns out) and charged me an arm and a leg. The second time it happened, I took it to an independent shop. They cleaned the carb, changed the plugs, the fuel filter, put the CORRECT air filter on, and reset the throttle cable that the Deere people had messed up. They also vacuumed out the fuel tank because there was water in the carb. When it happened again, the independent shop removed the fuel tank and found that the rubber grommet around the fuel feed line had disintegrated, allowing dirt and water into the tank. The mechanic said it was probably because of ethanol. Now it runs like new.

I just had this problem with my Honda Harmony HRB216TDA push mower. It sat for a few years after running the tank dry and the gas in the carb bowl likely went bad. It would only run when choked. If I took it off choke it would lose power and die, quickly when cold and a little longer once hot. I replaced the air filter, spark plug, and carb. Now it runs great.