mr-ranger 79 , i'm afraid arguing back and forth about pcv function has gotten everybody away from your original problem. sorry bout that. now whether or not a breather is deemed necessary or not , we all should agree the presence of one would not cause your problems . they all came factory with no issues. the engine gets its air through the carb, which is more than likely the culprit. by running better with the hose off versus plugged your air/fuel ratio is probably off{too rich or airflow choked} check adjustment of mixture screws and if equiped check choke to make sure it opens fully, the additional air thru the open pcv hose is merely making up for the lack of airflow thru the carb. hope this helps, and sorry we all got off track