need some help with my honda i recently bought. its a 20 hp 4 stroke bf. it hadnt been used in about a year. when i bought it i started it and it turned over and idled fine. but once out on the water when ever i gave it a bit of gas it nearly stalls all the time. i got the motor serviced and got the carbi cleaned, also changed the fuel and made sure there were no air leaks in the fuel lines but the problem still persists. could it be the fuel pump or is it possibly something else?