Re: Nissan 5hp Spark Plug gap
Your Factory manual is correct. There should also be a red sticker inside the lower cowl with that information. Proper gap is 0.8 - 0.9 mm, (32-35 thousandths of an inch) or a "tight" 0.035 inches, if you have the old-school non-metric gauge that only reads in 0.005" increments.
Best plug to use is the NGK DCPR6E in Nissan/Tohatsu 4-stroke outboards.
As always, it is preferred to use a wire-type gauge for setting plugs.
Keep in mind that plug manufacturers' products are used in a number of applications, and they cannot reasonably be expected to give proper specs for every possible use of the plug.
