My 9.9 Merc was running perfectly and then died. After determining the problem to be fuel related and replacing the fuel line barb, fuel filter and housing and then removing the carb to determine if anything looked faulty I re-installed and the motor would still not run. Only after manually depressing the accelerator pump will it run and only for 3-4 seconds, to keep it running I need to depress this buttom every 2 seconds. Is there something I am missing??? Thanks