Briggs & Stratton 9L902 lawnmower? My lawnmower won't start, even after pushing the priming button. Sometimes it...

My lawnmower won't start, even after pushing the priming button. Sometimes it runs for about 3 seconds afterwards stops.

It has a new spark plug & unusual air filter (and I oiled the filter). I've tried fuel cleaner and carb cleaner.

When I remove the gas sunhat, it doesn't start. When I remove the air filter, it doesn't start.
When I leave it for a daytime or so, it doesn't start.
It has a cover on it when not in use and doesn't sit out surrounded by the winter months.
When I push the red primer button, I can see a jet of fuel shoot into the proper hole.
The gas doesn't have dampen in it and the oil is new/clean.
Some of the answers I read mentioned a "float." I don't see anything that looks similar to a float and I don't know where an air squirt is. Possibly I should check these?

Thanks to everyone with suggestions.
Thinking of buying a home near a slope?
Answers:    I believe that engine has the carburetor mounted resting on the gas tank. There is no float and no adjustments. It is a diaphram carburetor. It desires to be removed, cleaned and put back with a hot diaphram and gasket. Make sure that the fuel tank and fuel pick up tube are clean also.
How do i return with rid of cockroaches...
Check this connect out. It takes to long to explain all things to look for; it have allot of information on trouble shooting and general information on small engines.

http://www.repairfaq.org/sam/lmfaq.htm

BTW The float is located under the carburetor. You own to remove the aluminum colored cover to see the float. It helps regulate how much fuel is being deliver to the carburetor.

Hope this helps.