actually it's just the opposite. one of the first things i learned in basic engines was that water(moisture) when you spray it in the carb of automobile evaporates creating a lean condition. causing the combustion chamber temps to rise rapidly and break up carbon deposits in the engine. while that's automotive , there is no difference here. water when heated turns into a vapor(air) which causes a lean condition. therefore you need to richen the mixture to even out the addition of humidity(moisture+heat=air).