Dave, here is another DynaMix that draws fuel just fine using only muffler pressure. This is a brand new .91 I found a whaile back. I have 3 .91s now, two ringed and one ABC. The ABC is a Diesel conversion.

Also a shot of my Webra Dykes ringed .50 Diesel conversion turning a Graupner 12x7 at about 9,650 with the stock baffled muffler and 9,950 with the Bisson pits in the picture. Its a fine Diesel.