Small Engines (Lawn Mowers, etc.): Honda riding mower problems, honda ht3813, fuel issues

Question
Hey,
   I had a question about a Honda HT3813 2-cylinder liquid cooled riding mower I am fixing. I have cleaned the carb and the whole fuel system because it had black fuel in the tank when I got it. It starts up great and runs great for about a minute, then dies. The battery is totally dead so I have to jump start with a battery charger. I think it's just the battery, but wanted to make sure I am thinking right. Does it require the battery all the time, shouldn't it run off itself? Just wanted to check and get other ideas. Thanks for your help!
                                     Josh

Answer
They will run even with no battery once jumped. Sounds like your carburetor is gummed up and needs a totally rebuild by someone knowing where all the jets and fuel paths are to unplug them. Yours sounds like it will be packed with gas that has turned to gummy varnish. People rebuild them all the time just by swapping the parts in the box, then wondering why it still has fuel issues, and won't start, thats not a rebuild. You must unclog all ports, main jets, and fuel paths in the carburetor.  This is a delicate job, even more so on a Honda, their parts are 5X higher than other engines. The needle float valve alone is almost $34.00........Tom