No. It will increase by the % increase of the new engine multiplied by the % that the original engine was of the overall weight.
e.g Original wing area 100sq." original weight 100oz.Original engine 20oz( 20% of o/a weight) Wing loading = 1.0 oz/sq"
New engine 30oz. New weight 110oz , New wing loading =1.1 oz/sq". i.e 10% increase.
Engine weight increase % x original engine % = 50&x20% =10%.
I'm sure there's a better way of explaining it but I hope the above helps.