Just bought two SAF-Air M12175 (Rotax) quick drains and installed them at first oil change. I tried to get the level on the Rotax correct and ended up pouring in 3 liters of oil in each engine (twin) . After first flight (next day) I checked the oil level and it's a bit high so I tried to drain a bit off by using the quick drains. Cannot get them to drain, I'm surprised as I have one in my RV and it works fine. Don't know if the ones for Rotax operate different. They do push up but only a few drops came out of one and nothing came out of the other. Wandering what I'm doing wrong as I doubt I got two broken ones?