You have already checked it and the only way to repair is to replace the check valve body. This is a very common problem with Zama's, they use poor quality check valves which are easily swollen by many modern fuels and carb cleaners. I suspect you used some kind of cleaner while you had it apart and in this case was the cause. Check valves on these things should only be cleaned out using some sort of spray lube rather then cleaner.

Thanks for the quick answer. You are correct, I used Gumout small engine spray. The purge valve works fine but the other seems to be the problem.
I'll start looking for a primer body.