Slowing down on own from plane 5.0 OMC

[94 Sundowner]

94 OMC 5.0 I added fuel stabilizer and since then from planing the engine will slow down from 3K rpm to 1K rpm without dying out , then it will sputter and make a popping noise from the engine compartment probably backfiring . I have a video of this but this site wont allow videos . I will shift back into neutral and start over again to plane and 5 to 10 min of planing it will repeat itself over again . I have since then have had 2 different fuel ups of 91octane that's all I use anyways is 91 . Changed out spark plugs and the water/fuel separator.

 

[vasy]

Upload to youtube or similar and put a link here.
Could be some crap in carburator.

 

[Scott Danforth]

you are running out of fuel

could be dirty fuel system - start at the tank, and inspect/clean everything until you get done with the carb.
could be plugged fuel vent - clean fuel vent.