Posted for "Jack Cowell" <jcowell@nyc.rr.com>:

For what it's worth, this "burping" also happened to Mike Mahar when switching tanks on his IVP (which I now fly). Mike' above-10,000-feet solution is to always go to full rich with the low boost pump on before switching. In the 100 hours I've been flying, the Mahar system has always worked for me. No burps. Clean shorts.