The fuel shutoff solenoid?

It is getting 12v with the switch on.
Tank has clean & fresh diesel.

The fuel shutoff solenoid could have failed. Not allowing fuel into the IP even with 12v supplied.

Thanks.
Will check tomorrow.
More to follow.

Good, you are making progress!

Does it start quickly each time? Always start quickly, then dies?

engine starts but dies
 

No. It takes some effort to start each time.
Will ck the shutoff solenoid today.
Thanks.

Engine
 

No progress today. Same. Engine starts the dies.

Press the accelerator pedal and does not work. Stays idling.

How do I test the Shutoff Solenoid?

Make a jumper wire to apply 12v directly from the battery to the fuel shutoff solenoid. The solenoid should click when battery voltage is applied. But it sounds as if you may have more serious issues. Hoping for an easy fix.

Did you get the throttle arm positioned correctly on the shaft?
I would be prepared for a runaway. I have had several pumps start up and just idle (very poorly) and then all the sudden it goes to full throttle. 3 out of the 4 pumps that did this had sat for a year or more with bio diesel in them. It's an easy fix, pull the top cover off of the pump and clean/work the governor.
I do this to all questionable pumps now before I run them.

engine starts but dies
 

Thanks Anders.
Will check that.