I was having the same issue when i started out. I couldn't get the 2 draw to work at all, and when i did it sounded like garbage haha. There were a couple of things that i did. First of all i made sure that the harmonica was clean. Take it apart and clean it from the reeds to the comb. Then to make sure your reeds arent shot carefully
I'm having trouble with the 2 hole draw in general (any key or model). I know this is a very common problem, and I thought I had achieved a decent tone on the 2 draw, but now I have doubts.
I can draw very softly with relaxed embouchure on the 3 or 4 - using barely any air and sounding the note as quietly as I can. When I move to the 2 hole draw with the same minimal air stream and relaxed embouchure, I end up with NO sound. When I draw a little louder on the 3 or 4 holes and then move down to the 2 hole draw, I can get what I thought was a pretty good sound - but it's not as loud as the 3 or 4 draw using the exact same air stream and embouchure.
Please try this exercise and let me know your results. Can you use the same air stream/embouchure to draw holes 2, 3, and 4 with the same volume, or do you suffer from my problem? Can you maintain good technique but still find a volume low enough that the 3 draw will sound but the 2 draw will not?
Basically I'm worried this is a problem with my technique and not just the fact that larger, lower reeds require more force to vibrate.
Is this a problem with my technique?
Is it just the nature of the larger reeds, in that the larger and lower reeds require more air?
How can I tell the difference between a technique problem and the natural effect of larger reeds?