We bought a 1984 Baja in 2016. It ran great for several summers. In 2022 we had about $3k worth of work done to it that included bellows and a new starter. Never had any work done to the distributor or spark plug wires. Last summer we got stranded once when the engine stalled out under load in the water on July 4th. My husband did the winterizing and then the summer ready and we tried to take it out this year and see what we could figure out. He decided the fuel pump was bad. It’s running a Chevy 350. I think it’s an Alpha outdrive. Replaced the fuel pump and filter and then ran it on idle on the driveway for hours and it was fine. Took it out today again, and again, under load it stalls out. Today it wouldn’t start back up at all. What’s the next thing we should try? I’m eager to learn. But no idea where to start.

Is the boat currently not running? You need fuel, compression, and spark for it to run, figure out which one you do not have.

Also, running on land for an hour is not a good idea. Much less water flow from a garden hose than the lake.

Read this: Pair of 2007 525efi flop at same time

Could be possible, short answer was he replaced rubber fuel lines.

Let's recap: Last year boat stalled and stranded you once...and then? Reading between the lines, it appears that the boat ran okay for a while, as it was running when your husband winterized it. Husband decides fuel pump is bad...via some sort of Great Carnac inspiration or observed issue? Replaced fuel pump, it runs on the muffs okay at basically idle, but won't run strong enough to get you on plane on the lake? What did you have to do to get home...just idle in?
What carburetor? 2 barrel, 4 barrel...Holley or Rochester? Has classic symptoms of the carb needing "rebuilt".

You bought the boat 8 years ago and never had anything done to the distributor??? It needs a dist cap and rotor for sure and new spark plugs.
Don't know what ignition you have but being a 1984 it may need points and condensor as well.

Whoa...I didn't see the part about 'bought in 2016'...