my 2-pipe (deep well?) Jet pump won't achieve more than 49 psi, measured on pressure tank. 1) How to clear jet?

Pressure tank won't hold preset pressure. I pumped it up to 28 psi, cycled the tank a couple times and it was down to 22-23 psi, which seems to be cut-on pressure??? Is replacement the right thing?

I know that won't address the feeble pump problem.

Can't diagnose a pump online, but you can check your system for LEAKS, or obstructed intake lines first before you change the pump. Both conditions will hamper the performance of the pump/system. Bad check valves can also affect system pressure. In short, before you guess do the troubleshoot and pin down the problem. Might be worth the bucks for a professional look before you start changing stuff that may not solve the problem, especially in older systems that have gone without regular routine maintenance.

1. When you say it won't get over 49#, are you saying that it gets to 49 and cuts off, or it gets to 49 and just keeps on running but won't get any higher?

2. To set your pressure tank, you must first drain system pressure to zero. Turn off the pump and open a faucet. Let it run until system pressure gets down to zero. Then you can set your tank pressure to 2# BELOW the cutin pressure. So if the switch is set to turn the pump on when pressure drops, for instance, to 30 psi, then you will set your tank pressure to 28 psi. After that, with the system running, the tank pressure will go up and down but should not drop below 28.

It sounds like you were trying to set your tank pressure without first draining pressure on the system down to zero. That won't work.

3. How old is that tank? How old is the pump?