[Motor31]

I'm assuming you have a cable operated valve. It's sticking because of the cable not a sticky valve. Use some lube on the ends of the cable. The handle end and then inside the sliding basement door the valve end is located on the same side of the trailer as the handle. Apply some spray lube to there and it should get easier to operate. In my case I did away with the cable entirely 4 years ago and just use a handle operated valve. Since it's right there at the back of the sliding door it's no big deal to operate it to drain the black tank once a week. I'm dreading having to replace the grey valve as I'll have to either go electric or use another cable system. It's located under the trailer in that big black plastic bulge where the sewer pipe enters the belly.