Yanmar 4JH3E Fuel Problem

[Porthandbuoy]

I've bled through to the secondary on-engine filter with sparkling clean diesel.
Engine won't start.
Cracked the inlet line to the HP fuel pump. Diesel there okay.
Slackened the supply pipes on the injectors..
No diesel.
Cranked the engine over for 20 seconds a few times.
Still no diesel to injectors.
Bypassed the engine lift pump and put electric pump in the circuit because my fingers were developing callouses pressing that damn priming lever..
Diesel is flowing through the HP pump and back to the tank via the excess fuel line.
Still no diesel at injectors.
Clamped excess fuel line to try and force force diesel up injector pipes.
Still no diesel at injectors.
Moved throttle to various positions and cranked the engine over a few times.
Still no diesel at injector.

Stop solenoid isoperating and releasing okay, but no fuel is getting past the HP pump/governor to the injectors.

What could be the problem? The system is now pressurised, so I'm not sucking air in.
What else can I try before calling in the pros?

 

[ST840]

Have you changed the fuel filter?
I only ask because you put the emphasis on "sparkling clean fuel". Suggesting that maybe you had dirty fuel before ??

 

[Porthandbuoy]

Have you changed the fuel filter?
I only ask because you put the emphasis on "sparkling clean fuel". Suggesting that maybe you had dirty fuel before ??

Oh yes. After draining and cleaning the tanks and installing a 2nd filter and a pump so I could re-circulate new fuel.