I have 115 hp...set all winter, tried to start it up. Started pretty easily but runs about 10 to 15 seconds then stalls..everytime. I can keep pushing the choke on the ignition and it will stay running. Or I can keep squeeezing the primer bulb and it will keep running. I went ahead and replaced the fuel pump with a new one...same results. Any ideas? Could I just have bad gas or is there something going on with the carbureto?r