I have a 1993 OMC 4.3L. Sometime when I first start it after it has sat over night it will run for about 30 seconds and than die. I can get it running by loosening the fuel filter and starting it. Once it starts I shut it down, tighten the fuel filter and restart it and it runs fine. This only happens when the boat sits for a long time like over night. Once it starts it runs all day long and I never have a problem starting. I thought it might be the anti-siphon valve so I changed it out and still I am having the same problem. Is this a fuel pump problem or something else?
