'Happened to me once. May halong tubig yung fuel ko. Pinababa ko yung tangke ko para i-drain at para na rin linisin ng husto. Once I got the tank clean, pinalitan ko na rin ng fuel filter tas pinalinis ko yung carb ko para sigurado na rin. I thought to have my fuel pump cleaned, checked or replaced pero gut feel ko was overkill na yun if I did that. Turned out I was right.