I have a 2000 50 hp Johnson on a pontoon, a fuel problem started last fall and is getting worse as this summer goes on, it will start and run good for a few days and then i could be out on the lake putting around and stop for awhile and when i go to start it it will not. i have to remove the fuel fitting from the motor and prime the bulb with a pointed object in the end to open it as i prime the bulb, i reconnect it to the motor and pump primer bulb and it will start. it may be good for a few days and it does it again. sometimes just sitting at the dock for the week, i come up on weekend, no go. anyone else have a problem with this. i have changed primer bulb and fitting for motor with oem parts. HELP