In a sauce pan, add onion, celery, carrots, potatoes, bouillion and the juice drained from the clams, cook until tender under medium heat. Melt butter and stir in 1/2 cup flour wisking until smooth. Mix the last 1/4 cup flour to the bouillon veggie mixture stirring constantly until smooth. Add sour cream, pepper, salt and butter/flour mixture and the clams. Heat 2-3 minutes stirring constantly, but do not boil. When clams are cooked too much they get tough.