Bought a new 1162 and when let go of trigger it wont stop pumping. I have to disconnect the air hose to get it to stop. I am using between 85 and 100 psi.

blockage in the wand nozzle jet

Should have done it when you had everything unhooked.

Rather than disconnect the hoses I use the trigger unit from a plastic spray bottle to pump the fluid out of the PS reservoir. Just unscrew the spray tip on the trigger unit, drop the tube section into the PS reservoir and pump out the old fluid into a container using the trigger. (If the plastic tube has a tiny filter on the end just cut it off before you insert it.) Then refill the reservoir and take the car for a short drive to circulate the new fluid. Then do it again. Empty and refill.

In a few days or a week, repeat the process (2 more empty and refills)and you will end up with nice new fluid in the system. If you like do it a 5th time in a week or so (1 more empty and fill) but at that stage you should find you are pumping pretty clean fluid out.

Not the most efficient system but it is very easy to do, takes little time and you do not need to go disconnecting pump lines which I would rather no do..
I do it this way on all my own cars every few years because it is easy, clean and works well and keeping the fluid clean and fresh means less wear on the pump due to contaminants and fluid deterioration.

If you get air in the system because you run the fluid level below where the lines fit to the reservoir don't worry. The air will be removed when you drive the car and turn the steering wheel back and forth. I don't run the fluid below the line connection when I remove old fluid from the reservoir.

Just unhook harness to pump motor

This means the flood circuit is triggered. There is a leak in the dishwasher causing water to collect in the motor chamber. The leak is usually through the door seals or broken hose. Disconnect mains electric and water connections and pull dishwasher out from under kitchen bench. Tilt it from side to side to get the water out from under the base. Wait a little for water to dry up. Reconnect mains power and turn on to see if pump stops running. As mentioned source of leak needs to be fixed.

Leaking "O" ring in control button.

This happens when air gets inside the hose. An air bubble of sorts is in the hose and will not build pressure until you blow the air out of the line. Start the pressure washer, turn on the water. pull the trigger on the gun. It will spitter and spatter and come to a trickle. release the trigger on the wand. Pull the trigger again and it will eventually work it self out.

Disconnect hoses.
Look for kink in water hose.
Check incoming water connection for filter washer
Replace filter washer
If you don't have a filter washer, put one in.
Hook up water, and turn on
Water should come out other side of pump.
Turn on machine.
Do you get pressured water out of pump.
If no pressure, then pump is suspect
Hook up washer hose without gun
Does pressure come out of washer hose
Finally, the gun trigger may be bad.

We had to buy guns now and then.
Search for pressure washer guns
Following link shows guns we used:
http://www.ultimatewasher.com/pressure-washer-trigger-guns.htm

that is sure signal of insufficient water supply!

try easy solution first:
make sure that your mains is fully open, that tap on whihc hose is hook up is fully open and hose is of "decent" diameter to allow sufficient flow.

if above solution do not work then you need to make another, more difficult arrangement:
prepare 20litres pressure tank with inlet connected to mains and outlet by short hose to power washer, fill it with water from mains, keep it under mains pressure and use karcher power washer normaly. this will solve water supply problem. twenty litres will last about 2min, because it is re-filled, under standard pressure therefore it will last about 3min...

third possibility is to stop washing...

if you find my advice helpfull, please do not hesitate to left the comment and vote for me, thanx!

I have a similar problem and diagnosed it to be a problem with the gun. I spoke to a technician that services this pressure washer and he walked me through all the diagnostic steps. The pump is working because there is pressure being built up and the gun sort of works because you can get water out before the washer is started. The technician said that the mechanism inside the gun is either clogged or broken. I am going to Home Depot or Lowes to purchase a new gun and will try it tonight. Guns are only about $30-40. He said generic is fine as long as the thread matches and PSI is in range. Good luck!