I agree with all who said to check fuel filters and their corresponding seals and connections. Additionally, check any shutoff valves or bleeders, or anything else anywhere along the line all the way from your tank to the engine... I have a shutoff at the tank end of my fuel line that had been shut off (by someone else), which apparently didn't "TOTALLY" shut off fuel flow... so engine would idle fine (drawing just a tiny trickle of fuel) and run at higher RPMs for a while as well until eventually the suction would be too great for the engine to pull fuel against, and it would stall... after waiting a while, and checking/replacing fuel filters... all would work fine again (pressure slowly equalized)... then again... stall after running fine for a while. Everything pointed to fuel filters, but filters looked pretty good. Long story short: Even though the filter is the most LIKELY thing starving your engine of fuel, it isn't the ONLY think that might do it. If someone else was working on your fuel system (as you stated), I'd make sure they didn't inadvertently close a line, or open a bleeder, or vent, or do something else related that left your boat in a different state from how you think everything is flowing. It's unlikely, but possible that you'll find something else out of place along the way if you trace the fuel's path... plus it's a pretty cheap and easy step to check that. I wish I had checked before tossing multiple rounds of fuel filters, and changing them while bobbing around at sea in a state of panic. Just food for thought.