I was getting some type of reversion, never could idle right without loading up. I have EMI thunders with the short ss risers. My cam is a crane 551/531 lift. 226/236 duration@050 114LBA. No matter what I tried it wouldn't idle with the exhaust in the loud position UNTIL i spoke to Drew @ Drew marine. I installed shotgun silencers and dumped excess water out of risers with 1/2" water dumps
My Problem Was Sovlved. Drew said it doesn't matter what risers you have , if you dump water out less of a chance it won't get in..He said you only need a very little bit of water to cool the hose connections.

http://s1071.photobucket.com/albums/...t=a417b0c9.mp4