carb problems

[Stephen717]

Hello everyone. since my last posting I've done quite a bit more work to the frame to the point that I am nearly ready to swap the motor over and prepare to swap the body over. My current problem is that I went to start her the other day and noticed that the Monojet was leaking fuel. Not a big deal as I have 4 2 jets lying around. 2 of them are in pieces and need rebuilt. The other 2 came off a car with a running tri power setup (the guy was going a different direction and and someone snagged the middle carb before I could get to it so I bought the intake and 2 outer carbs). I have tried both and found that neither of them leak but when I try to start the truck (with either 2 jet on the 250) it sounds like it doesn't want to pick up fuel to stay running. I am a novice on carbs and have only ever rebuilt 1 with a friend (and he did most of the work) so I'm not sure exactly what's going on. Can anyone help with this?