The fuel pickup tube in your tank. check it. very overlooked and almost always sludge clogged, even in clean tanks.
Just remove the screen. I removed it from both our Sabres. It was one of the first things that I did on Victoria
when we bought her. Let the Raycor do it's job and catch gunk, it's far easier to clean the Raycor than to go spelunking for the stupid pickup screen. After I ripped it off our current boat, the amount of junk that the engine sucked up was amazing - it was a wonder that the engine ran at all.
Your problem sounds like a classic fuel starvation issue.