What kind of alarm? Long-intermittent, short-intermittent, or continuous? If continuous, then the ECM thinks you have water in the on-board fuel-water seperator, or the float is stuck, or the connector is corroded or bad.
Did dealer run HDS diagnostics? Should have. If so, what did that say? If not, find another dealer who will.
Simple things first. You said bulb get's squishy - that is likely either an air leak in the fuel line somewhere, or a bad low pressure or high pressure fuel pump. To test the LP fuel pump, try having someone constantly squeeze the pump up bulb while trying to get up on plane. Make sure the bulb is not collapsing when alarm goes off. If so, then you have a clogged breather tube to your fuel tank, or a partially clogged pick up tube in your fuel tank. To test for a clogged breather tube, just unscrew the fuel filler cap while running. To test for a clogged pick up tube, disconnect fuel line before pump up bulb and blow compressed air back through it into the tank - make sure the fuel filler tube is open.
Do you have an external fuel/water sererator in line? (You should have.) If so, check it for water, and make sure seals are tight and the fuel-in and fuel-out connections are tight and secure. If the filter has not been changed in a while, change it. Thay sometimes get clogged up over time and they will deteriorate over time.
If nothing helps, yet, then rig a clear plastic fuel line from your pump up bulb to the on-board fuel-water seperator. Try to get the engine up on plane and have someone look for air bubbles in the fuel line. Next, remove the bowl to the onboard fuel-water seperator and clean it out well. Re-assemble IAW owners manual. Make sure the float moves up and down easily, the bowl seal is in good shape and tight, and the fuel line connections are tight. Also clean the connectors from the two wires coming out of the bottom of the fuel/water seperator.
Next remove bowl to LP fuel filter, check seal, check fuel line connections, and reassemble IAW owners manual.
Drain the VST. On the back right side of your engine, you will see a clear plastic tube in a clip. Take it out of the clip and follow it to the base of the VST. Beside it will be a slotted set screw. Use a 10'" screw driver and slowly open the set screw with the open end of the plastic tube in a clear quart jar. You should get about a pint of fuel out of there. Inspect for dirt and gunk. If no fuel comes out, try blowing air back through the plastic tube to open it up.
Get back if none of that fixes the problem. I'm assuming the dealer actually did change out the high pressure fuel filter.