IF you post the Sears#, one can get a much better idea of what you have. Typically something in the format of XXX.yyyyyy

IF this is a smaller walk behind, chances are you may just have a small screen inside the fuel tank.

Question? are you sure the choke in pushed all the way in??

Two ways to find the fuel line start at the gas tank and follow the black hose coming from the bottom little bigger than cig. or one of them fat pencils. Follow this hose up towards the engine till you run into a plastic looking bludge. If this bludge has two clampy looking thinks and hose is running in one side and out the other you may have found the inline fuel filter.

Another way would be start at the carb. Should be at the front or front side of the engine depending on which model engine you have in the mower. Look for this Black hose again about the size of one of the fat pencils. Now if you have fuel pump on your model it will be mounted to the side of the engine and has this hose coming out both sides. If you model don't have fuel pump it will be after the fuel pump going towards the gas tank. If your model don't have fuel pump the gas tank should be mounted above and behind the engine you will find the inline filter some where between the fuel tank and the engine again following the black hose.

Sorry, should have given you more info. It's a B&S engine, 3.5HP It was hard to read the serial # but I think it's 1202 1249 E1 97 101FA. There is a black hose underneath, but no clamps etc....like you find on a regular mower. Maybe I'll take a look at that hose, pull it off and see what I come up with. And yes the choke is pushed all the way...I even played with it a little to see if I could get it to quit loping, but no luck....

This would have been better if posted in the walk behind mower section, instead of the tractor section.

A Briggs engine THAT small would only have a rudimentary screen in the gas tank.

The Briggs Model # would be 5 or 6 digits. (6 if > 9 cubic inches)
The type is 1249 E1

Your code is also missing a digit, but that's only the date and place of manf.
YYMMDDxx

Ok, if that's old flat head design you need to pull the plug, clean it, spray carb. cleaner in the spray can on it using wire brush scrub it. Now spray carb. cleaner down the spark plug hole and pull the rope several time. Look at the end of the spark plug using a paper match box lid check the gap on the plug. match box lid should just slide through. Install the plug and fire it up. this will fix it most of the time. if it don't then you need to remove the carb. off the gas tank and clean it out, also the stand pipe screen that sticks down into the tank that bill talked about. Last thing would be to decarbonize the combustion chamber. You do this by removing the head bolts (all the bolts around the spark plug) pull the rope till the piston it all the way up even with the block. Now spray carb. cleaner on the piston and valves scrub with wire brush. When done with the block spray carb cleaner around the piston and valves to wash any carbon that got pushed in the gap between the block/piston and block/valves. Do the same to the head and gasket.

You can ususally reuse the head gasket over several time Thick shinny gasket that was between the head and the block) reassemble the head and tighten the bolts (usually starting from the center and working out). Now fire it up again.

If it still runs ruff it probably worn out due to lack of oil or oil changes.

IF this is newer OHV engine about all you can do is clean the spark plug and the carb. Adjusting the valve lash maybe way over your head.