The Gemara in moed katan on Daf Tet Vav says that a Baal Keri is forbiddon from talmud Torah because he is mentally and spiritually impure. What makes him unfit for Talmud Torah, as compared to a Boal Nidah who is considered fit??
The Isur of learning Torah for a Ba'al Keri has nothing to do with his Tum'ah with regard to Terumah and Kodshim. Rather, it is a new Halachah that was enacted to prohibit him from learning Torah because of his lack of "Eimah...." This Halachah does not apply to other forms of Tum'ah.
Obviously, a Bo'el Nidah will need Tevilah in order to learn Torah, but he will not need seven days like the Tum'ah of Bo'el Nidah.
So what makes the Ba'al keri have this lack of "Eima....", wheres it would seem like a Bo'al nidah should lack these essential traits as well?
Once again, we are talking about the seven day Tumah of Bo'el Nidah. After the Bi'ah before Tevilah he is obviously of the same status as the Ba'al Keri.
I understand what you are saying, and thank you very much for your help. But i still do not understand why the Gemara makes the assumption that A Ba'al keri has no eima, yira, etc. what makes him different spiritually. It is clear that physical tumah is not the issue and i can excpet that but why doesn't a Bo'al Nidah lack these spiritual traits as well?
The Tevilah of a Ba'al Keri is not related to some mysterious "spiritual quality." It has to do with the fact that he his emmision came about during a period when he was not of the right mindset for learning Torah, since his mind was set on physical pleasure (i.e. Tashmish) at the time. This is referred to as "lack of Eimah," i.e. a person cannot study the Torah while such intense physical pleasure is on his mind. He must first immerse, reminding himself to change his mindset, in order to study Torah again.
As you pointed out, the same is true of Bo'el Nidah. At the time he was Bo'el Nidah, he had physical pleasure on his mind, and he therefore is disqualified from studying Torah until he immerses in a Mikvah.
When the Gemara says that a Bo'el Nidah is permitted in Torah, it means that after immersing in a Mikvah (to change his mindset) he is permitted to study Torah despite the fact that his Tum'ah still lasts for another seven days. A Ba'al Keri, on the other hand, becomes permitted to study Torah at the same time that his Tum'ah is removed, i.e. through immersion in the Mikvah. There is no person who retains the Tum'ah of a Ba'al Keri but is permitted to study Torah.