Been changing mine annually on my '99 Merc since new.
Never "relieved" any pressure, just uscrew and replaced. No problems here so far, don't know if there is another method, but would be curious to hear if so.
Fuel injected? If so as long as it's been a few hours since it's been ran, the pressure should of bled off. If you just ran it then it will have pressure. Either way some fuel will spill. Put a towel/rag under the filter and crack it open slowly.
Engine is the 350 MAG MPI Ski. I saw something when random searching online about turning off fuel supply or relieving pressure to stop fuel spray, but did not know of any fuel cutoff and did not know if pressure would be maintained even when engine had been off for awhile. Tks for the feedback
Just unscrew it. Did mine on my 98 tige last week. I needed to use one of those strap wrenches to get it off though. Don't forget to fill it up with gas before you screw the new one back on. While you are at it you should swap out your cap and rotor. My engine was running a little rough and swapping out the rotor made her super smooth again.