[COLOR="Blue"]The main problem is the adapter is not flush to the facuet anymore[/COLOR]

Sorry I do not understand the above.
Is it that the threaded part of the adapter is too long so that it cannot screw in all the way?

If this is the case how much of the treads are bare between the adapter and the faucet?

If the above is true you could:
1. Take the adapter to an appliance parts house and see if they can supply one with less threads. May even be able to get one at a place like Home Depot etc.
2. Get a fiber/rubber washer or O-ring of the correct size and use it to make the seal. It could go on the outside of the adapter or inside depending on the faucet. Be careful not to over tighten as that will deform your washer/O-ring.
3. If it is just a couple thread showing, wrap them with teflon tape and give it a try.