I have the same trike in My garage as I type this... The guys are right, Your float/needle valve is stuck open. It might just need a tap, but more likely is gummed up. I've worked on these alot over the years, good little trikes, but like Ponyboy said [b]>>>VERY<<<[/b] easy to tip over, both side to side or backwards. I've been riding ever since I was 7 (I'm 39 now!), and I still don't fool around too much on Mine. Too easy to get hurt. Start off slow, Practice tilting it over to get the "Hang" of what It feels like before/during when it happens(Yes It Will!!). Drop Me a line if You need more info. Parts/ manuals are easy to find online or on ebay.
Tall Shadow