I have a 4 week old kitten he is the runt and he is druling and having diahrea and peeing all over and he his very out of it I can't think of anything he could have got into and why all of a sudden he would start acting like this please respond asap

That small with that much fluid loss and "being out of it", I would suggest taking him to the vet immediately.

How are the other kittens and momma?

Could he have gotten into electrical wires?

Cat is right... the kitten is too young to withstand this sort of fluid loss. You need to get him to the vet pronto... please keep us posted!