Originally Posted by bullwinkle
Only 2 stroke I saw issues with this was 2-stroke outboards, in days of old-seems putting around in no wake zones would tend to foul plugs, they seemed happier when run hard. Never heard of engine damage from it, though.
I second this. The only area I have ever heard that 2 stokes needed to be run at full throttle more often that not was in older marine 2 strokes, which your neighbor, depending on his age, may be referring to.
I was told the reason for this was that you wanted to mix the oil/fuel ratio rich enough to protect the engine at full throttle under load, so when trolling or puttering along you were running a much richer oil/fuel ratio than needed for that use. This would sometimes cause plugs to foul. As mentioned, this was never anything that could cause engine damage, but certainly could cause it to be a bad day on the water if you fouled a few plugs.
This issue has been pretty much eliminated with the introduction of oil injection in the 2 stroke marine engines, so the oil/fuel ratio is adjusted automatically for load/rpm keeping it leaner at low rpm/load and richer as needed for the high rpm high load conditions.