I have an 2003 Proline walkaround with a 150 ob saltwater series. I just went over 100 hours on the engine and had the engine overhauled two years ago. My problem is while heading out my engine will shut off. The primer bubble will be flat like it is trying to get gas. I have to work it until I can get it to get gas back in to it and the engine works fine for alittle while and then it will shut off again. The bubble doesn't get hard like it use to. I was told this could be a valcuum problem and to change the bubble. I changed the bubble but it still doesn't get as hard. What could be my problem?

