B&S 18.5 Difficult to Start and Blows Smoke

Ok, the tank is drained and the carburetor is off the engine. Now, here's a stupid question. How do I clean it? There is no obvious way to open the thing. I can clean the dirt on the outside but I assume the problem is inside. I tried to upload a picture but it never showed up in my album. The top part of the carburetor has the throttle and choke valves and the lower part is like a 4 oz can in which I assume the pin and the floater reside. So how should I separate the can from the top? By the way, the valve part looks squeaky clean and no gunk.

at the bottom of the bowl you should have an electrical plug....and a space between the bowl and plug will have two flat spots for a wrench...untighten it it and the bowl and solenoid will come off

With regards to the fuel shut-off valve, I am a firm believer.:smile: But since my memory is very good, but very short, I had to take a label maker and write up a "gas on/off?" label and put it right where I can see it while I'm sitting on the seat.:ashamed::wink::laughing:

Success! I cleaned carburetor, drained oil, removed spark plug and let it dry for a day. By the way, the drained oil looks like water with no viscosity.
Today, I installed new oil and fuel filters, fill the oil and some gas. It started right away and after 30 seconds, the smoke was all cleared and the engine ran fine. Just finished cutting the lawn.
Thank you all for the suggestions and instructions. I couldn't have done it without you guys. In fact, I didn't even know it was cause by flood of gasoline through the carburetor. I thought somehow the piston ring was damaged. Next time when the tank is empty, I will install a fuel cut-off valve.