12Hp Briggs and Stratton trouble!!

Hi, drummerboy

I'm wondering if your air filter is clogged to the point of siphoning (by vacuum) oil from the crankcase into the carburetor. Is that a possibility?

Check the tube that comes from the crankcase. Remove it temprarily and see if motor will rev up without issues. If motor runs ok check the following.
Sounds like the valve spring compartment may be full of oil and you are getting the siphon effect mentioned earlier.
Remove the valve spring cover and if very much oil runs out the drain for the valve spring compartment is clogged. Open the drain hole with smail wire or ice pick. You may have to remove the carb to get to this cover.