Sorry, I don't have a clue except looking at the check valves. 
yeah i'm kind of kicking myself for not doing that right now but once i get time i'll hopefully get it fixed and then actually winterizr mine this yearHey their fellas, hope ya'll ain't mad at me.Dealin with personal "demonds". Things are gettin better
So, any how. I remember talkin back in the fall about "winterizing". I told you fellas about that I run some dawn dish soap thru mine, to see if that helped with my problem, which sounds kinda like yours, right now. Last week I finally got mine out and was delighted that it worked properly.. My thinkin was/is that the soap "coats" the internal check valves and pump. from gettin goulded. I'm sure the fact that I'm on a well and my waters on the "hard" side don't help...