Half A Head Firing?

[Biker Scout]

OK, I see there are some issues with the black head. Fine... But what the heck is going on with the Magenta Head? It's the newest head in the machine.

 

[artbot]

vapor lock. pull a very very gentle vacuum from beneath the cap (either the drain line or separate the union going to the pump.)

 

[Jack Knight1979]

agreed. Happens to me often.

I run flush through the top of the head via syringe.

That gets things going for me.