Suzuki ap50 loosing power in the rain wots wrong?

my 50cc scooter has been fine cince i bought it but when thear was some bad weather (lots of rain) it lost power a cuple of times but shourtly got going again. I was planning to take it to the garage after work wear I had to leave it in the rain all day. I tried the electric and kick start but no luck I am charging the battery tonight as it is dead. I know the bike was serviced in april had carb cleaned air filter cleaned oil done I have checked all conections are fine thear is bit of a oil leak from the tank and has been in doors for 5 days now I think it might work when I put in the battery but if thear is enthing you can help me to get it work if this dose not work. thanks