I did in the very beginning, but after a phone call to Paul who stayed on the phone and walked me through every step it works fine. I took the drum out dremmeled the hole a little larger to releive some of the pressure, sanded the top of the drum down so the magnets made better contact and sanded the sides so the fit is a little loose. I get very little flow out of the next or last port as it switches, but trust me it doesnt hurt the flow any at all.