Thanks for the post!

Just to confirm, how do you know the pressure is fine if it only runs one second at a time? Based on what you have told me here is what I think:

I would check all the lines or hoses going to and from the pump connections and the connections themselves to see if they were free flowing and to see if there was any sediment build-up or debris inside.
I would also check the wand for the same things. Take a garden hose and hold the trigger down to see if water will flow through it.
If all of this checks good it is probably a pump problem and I see that there are no parts available for this units pump. It could be that the check valve or unloader is sticking or some other pump problem.

Hope this helps, feel free to reply with more info and we'll get to the bottom of it.

- MTR