Gunnut, it could be you picked up some bad gas, with "settlings" in the low lying areas of the carb if equipped...there is a small slotted float bowl plug which should be unscrewed and drained into a clear container to see what comes out. Does your fuel petcock have a PRIME position? May also be sticking fuel valve (in closed position) or clogged inlet filter in the tank.
Get some GUMOUT CARB SPRAY CLEANER, pull the aircleaner off and look inside throat while twisting throttle, should see good stream of fuel sprayed inward. Spray a little in there (be careful of overspray getting on painted surfaces) and have a clean white cotten tee shirt rag to wipe up excess dirt and debris away...lift the slide gently and see how "free" it moves and clean all you can reach slightly more spray and clean rag. From here you can decide how far you want to go by starting engine and spraying short bursts into throat being careful not to bog engine.
Finally, there is also possibliilty that the float needle is sticking, or there is a small hole in the accelerator pump diaphram. Since your carb is 14 years old or so, even if you were dilligent, carb may need a good cleaning and rebuild (kit is about $35 USD). Likely you have the service manual, but there are exploded diagrams and details in the Self Help Tab near the top of the page to help you the rest of the way. Tell us how it goes.
