My pump is self priming in 5 or 6 strokes.
If your pump was working fine before the cleaning I would suspect that something is blocking the waterline or the checkvalve. Or maybe there is a bad bend on the line.:shg
If there is no blocking, then the check valve (a ball) is good and the rubber ring that produce the vaccum inside the pump need to be changed, if you can find it.
I don't know how many hours I spend trying to fix my old pump witch had the same symptoms as yours.
The problem was the rubber ring. It was not flexible enough any more. Since I could not find a replacement part, I tried to boil it, I try to put it in a form to expand it, I tri to put vaseline on it , every time putting back the pump together and trying it. No success!! :bh
I finally changed the pump.
Since then, I installed a battery
in my trailer. Now, I have a very small electric pump on the same waterline and the hand pump is the faucet (the spout). I still pump by hand when I just need a small amount of water.
The electric pump and the hand pump are about the same price. If you have a battery
or consider putting one in your trailer and can't fix your actual pump, my advice would be to keep it and buy an electric pump. It is so much more "confortable". Really!