Mouthy six month old

Question
How do  we stop the mouthy biting of our six month old springer spaniel.  He has plenty of chew toys and gets lots of exericse running and playing with our other older dog who is a terrier mix.  We will be getting him neutered very soon. We need to control this behavior before he grows any larger.  Any helpful tips would be appreciated.

Answer
This is a behavior problem that started when this puppy was young- like 8-9 weeks, and was played with using his mouth. By that I mean toys that encouraged him to use his mouth as a toy- tug of war, playing with him by grabbing his muzzle, his legs or his head so that he responded by using his mouth as at means to play. This problem is already 'larger.'

Six months old is pretty old to be retraining him but it is doable.
Neutering will help, but that is not the cause of this issue.

He needs to go through basic obedience school and to be taught some manners. Telling him sharply, NO BITES will help, but again, that should have been done months ago.

If he starts to mouth you when playing, you need to stop the play calmly, tell him NO BITES and walk away. He will eventually get the idea.

When he does this, distract him with a different toy that he can play with by himself.
He needs to associate the fact that his mouthing is what ended the play and the words are sharp so that he understands it is not acceptable at all. Your leaving the area reinforces that idea as well.

A trained dog is a happy dog, so get him enrolled in puppy training soon. That will be your best ally.

Find him some training and do some of the above consistently. Please let me know how it goes.