Decarbonize - still needed with unleaded fuel?

[38racing]

Manuals for older briggs engines did list decarboning as a maintenance item. cannot recall if seafoam claims to remove carbon buildup. and do water or tranny fluid entered into air intake of running engine not do that.?

[EKAP1200]

Manuals for older briggs engines did list decarboning as a maintenance item. cannot recall if seafoam claims to remove carbon buildup. and do water or tranny fluid entered into air intake of running engine not do that.?

Water sprayed from a garden spray bottle into the intake while the engine is running mid range is an old trick for removing combustion chamber carbon , your showing your age now.... but seriously I have been in the habit of adding ( Seafoam ) to the crankcase before an oil change , and in the fall I mix it with the 5 gal gas cans to add to all the engines here.