Sorry yes, raw water. The no power to pump is obvious, can you explain how it would/wouldn't work if under full pressure?
There is a pressure sensing switch on the pump that cuts out the motor when a certain pressure is reached. That keeps the pump from running when there is no demand. If there is a blockage, the pressure switch may be triggered stopping the pump.
The switches do go bad and can be replaced but in my experience, if the pump is old, replace the whole thing. First though, you need to make sure you are getting 12 volts at the pump connection and that the ground connection is good.
You also mentioned that originally the pump ran and water came out of the fitting but later on it didn't run.
Let it sit for a longish time like overnight and then try the switch. Listen for the pump. If it starts and stops, there is a blockage in all likelihood.
Often the first time you start one of those pumps there is residual water left in it and that is what spurts out. When testing make sure the flow runs for a while like 30 seconds.
Also, it is possible that the strainer/scoop) on the hull bottom is clogged with growth. There is a way to tell but you will need to remove the hose or pump depending on how it it plumbed.
You shut the sea cock, remove the hose and carefully open the seacock. You should see water flow in. Close the seacock!
Most likely you have dead pump or bad connection.
