Is it my fuel filter?

I'd check the hose in the FCC, and would also check the anti-siphon valve in your tank.   if you have a fuel pressure guage, that could be an issue too, you could check the pump pressure... that could also be the issue.   Fuel filters are easy and cheap.   Probably the first thing I'd change just to make sure that wasn't the issue

Probably not available at an auto parts store. N3 will have it. You might want to get the "tube inside the FCC@ while you're at it. Any place that sells the filter will know what you're asking for.

Do you think beating on the FCC definitely helped? If so, that would make me think the high pressure pump itself was on the way out. Of course, it could have just needed time to cool off, which would point to the pump again or one of the relays.

First determine if your fuel pumps run by listening for them to spool up pressure when you turn the ig key to run, (about 2 seconds). The fuel pump power is supplied from the main battery with a separate lead, about a 10 gauge wire with a 50A fuse and fuse holder located in the battery box. Looks like a short, black stubby cigar. This holder has been known for corrosion and intermittently losing power to the fuel pump. I recently cut out this fuse and holder and replaced it with one from NAPA, and eliminated my erratic stalling/no start condition.

Tried to take the canister off to inspect the filter and I can't get the canister off. I assume it just spins off.

I took the boat to the good folks at H2O Sports in Dothan AL. They already repaired it. It was the fuel filter and he said that it took 2 people to get the old one off. Same day service!