In nouns that end in <ful> the pronunciation of the ending is usually fʊl. Examples:
bucketful cupful pocketful spoonful
On the other hand adjectives with this ending usually have the pronunciation fəl or fl. Examples:
awful beautiful doubtful useful wonderful
Adverbs ending in <fully> have the pronunciation fəli or fli. Examples:
frightfully gratefully hopefully spitefully
2013_08_04