Hey grumpy,
Thanks for the suggestions

Yeah its pulsa-prime...
Tanks been cleaned out mesh is clear on the pickup even took the screen off the jet to try. Its just using whats in the reservoir then stalling.
A blockage for sure, but every pipe and gallery seems clear....I havnt checked for a crack in the main pickup, but it still bringing fuel up to prime so i doubt its that....
The prime does take a second or 2 to release after its pushed, not like a victa type, but it does have a tiny check valve so i guess thats normal?
There is another ball bearing in the lower left of the primer chamber, a port block off? Will this or its position have any relevance mate?
There appears definately a blockage maybe mecanical (part inside has shifted?)
Im missing something...
And also not the tank...its too quick too stall and the cap is clear...
Can i burn it now???? Gawn let me lols