Help - 2500 running rough as old boots

[Driveshield vehicle track]

A bit of a daft question but have you checked that your choke hasn't jammed on.?
It happened to me

[Goldstar]

A bit of a daft question but have you checked that your choke hasn't jammed on.?
It happened to me

No such thing as a daft question - only the question not asked I have thanks, the cams are clear with the choke in and the jets are up with the choke in.

Jules, BDB which i think are correct. Mech fuel pump which seems OK, I have also disconnected the fuel pump and run it on the bowl contents to see if overpressure was the culprit but no difference. I have thought about sticking my Facet pump in, instead of the mechanical one, to see if that makes a difference

Both butterflies open at the same time/rate

Over the weekend I took it all apart, inlet manifold off, exhaust manifold off, both back on with silicone gasket round the inlet manifold inlets, carbs changed back to the originals, all reset, choke checked for operation, both throttles checked, needles re-seated flush with bottom of piston. Didn't have time to try starting but I'm not sure we have found anything significant, inlet manifold gasket in place and undamaged, no splits/damage to inlet manifold, no lumps of carbon in the exhaust manifold.

Getting the cam cover off next to see if the valves are sticking or something as fundamental as that.



Thanks all for inputs so far.