Small Engines (Lawn Mowers, etc.): Oil comming out exhust, fresh oil, fuel cap

Question
I have a Bolens BL00 weedeater.  it has not ran right all year. It has fresh gas.  I took the thing all apart including the carburetor and put back together. Now, it will run but very smoky and oil seems to be coming out of the exhaust.  What do i do now?  I am concerned i took the filter off and squeezed it out. do i have to put fresh oil on it and is this my problem?

Answer
Thew black substance coming out the exhaust is a mixture of unburned gas and oil.  This usually comes from flooding the engine or fuel is running through the main jet all the mine meaning the inlet needle is not seating.  

First check the fuel cap vent.  If the tank will not vent it could become a pump.  If not that remove the carb disassemble it and install a new kit being sure you set the needle correctly.  Hope this helps