Hi I have a 115,000btu goodman furnace and when I go to start it in attempt to run but the burner does not stay on. It sound like their is a lot of condersation inside the unit

So the burner lights, then shuts off? If this is the case, it's probably the flame sensor. It should be a large wire looking thing that goes in front of one ofthe burners. Pull it out by taking out the screw holding it in, then clean it with sndpaper, or steel wool, put it back in this may fix your problem.

Also look for the red light inside the blower door, it should be flashing once.