Help...!!!!
I was driving my astro yesterday when it just died.
I have checked the spark, its fine.
Doesnt seem to be getting any fuel.
I poured a small amount of fuel into the top of the carb and it started, until all that fuel was burnt.
Is there a fuel cut out switch.
Or is it a more difficult problem.
The van has had no problems with running or starting up till then.

You probally have a fuel pump issue.

What year is your vehicle? What size engine?

When you turn the key on, can you hear the fuel pump priming? Another good spot to check would be the fuel filter.

The van is an 1985 model with the 4.3l engine.
I've had a look and it has the mechanical fuel pump.
Is it possible to replace the mechanical pump with an electric one and what sort of psi pump should I be looking for.

On that model fuel volume is more important than pressure.
Disconnect the line that goes into the carb. Using a sutable container, spin over the engine and see if you get a good volume of fuel.
I would replace the mechanical pump instead of going through the trouble of installing and wiring an electric pump.

I managed to disconnect the pipe to the carb and when spinning engine over, no fuel comes out.
I have removed the pump from the engine and does seem to be shot.
Trouble is im in the uk and cant get hold of that mechanical pump too easily.
Much easier to fit an electric pump. How much flow should the pump put out

The fuel pressure on those should be no more than 9 psi. I think 4-6 was about average.
You might have to install a regulator to control the flow of the fuel pump to the carb.