Have you tried disconnecting the fuel line from where it connects to the bottom of the fuel tank. There should be a stop tap between the tank and that connection, when disconnected slowly open the tap and see if the fuel runs freely, if it doesn't then I'd assume diesel bug. It forms like a jelly against the outlet in the tank and although you can push a stick or whatever into the tank the jelly closes up behind it.
The only way I've dealt with it for instant results is to push a long [at least a metre long, 2mts better] piece of clear plastic hose onto the outlet, open the tap and suck [yuk] you do have to give a strong suck, hence the length of the pipe, but you'll know when to stop, believe me .
That should get you going again, I've not found it nescarsary to replace filters, just give them a swish in some clean diesel.
Get some Marine 16, it's the best, it'll kill the bug and also dissolve the residue which others don't do.