pitts muffler
I have an o.s. 61 with a pitts muffler mounted ina great planes ultimate 40 bipe sideways. I cannot get the muffler to put out any pressure to the tank and as soon as the tank gets half empty the engine quits. The lines and nipple are all clea. I even pinched off one pipe still nothing. It blows great with the standard muffler. Is there something missing in the muffler? looks like just a box with 2 tubes coming out so how can it build up pressure to the nipple?