Thanks Dale. I have had my suspicions about the horn. There may be a reason it was given to me after being used as a Christmas gag gift.
I often hear a gurggling sound even though I keep the water valves drained. I also recently replaced the corks on the water valves. I have a feeling the third valve leaks a bit as I've been finding a surprising amount of fluid in the bottom cap after playing for a while. I'll have to pull out my el cheapo flugelhorn to see if it improves my sound any.
The more I read here the more I wonder if I've bitten off more than I can chew. Even though I once played for eight years and could blast out a high C, I wonder if I really could have been considered a real brass player. I certainly never had the guidance or the discipline to properly develop my playing skills as many of you have.