Old Leafsprung Land Rovers

Hi guys, Ive had problems getting my 2.5 petrol engine running good for a while now. (revisiting the problem now worst of winter has passed.

So As we are now, refitted a duceilier distributor with new points,(gap checked/adjusted) condenser and plugs.

Still had problem, will idle ok, but any sight of gas and it runs rough as a dog when rev'd.

So attention turned to carb. swapped the weber for used zenith, same problem, the mixture screw on this zenith didnt seem to do owt, so..

brought a new zenith and fitted today, still the same symptons exist...
I got it running on LPG too,same problem and as the carb dosnt really adjust the fuel/air mixture for gas ive started thinking its not the carb.

I'm now running out of ideas  , so any tips would be most apprechiated...

Thanks in advance

Timing, plug leads and plugs would be my next to check items....

The carb will have zero effect on LPG unless it's majorly ****, e.g. **** and in two halves. For testing purposes I had the worst carb for a 2.5 fitted to mine for an hour or so, the 34ICH and other than being slower it still ran smoothly throughout even when the throttle was to the floor.

In no particular order I'd check the following:

1) Air/vacuum leaks. Check the inlet manifold gasket is in good nick and nothing is loose, and the vacuum hose from the inlet manifold to the servo is attached and in good condition. Leaks in either can cause what you're experiencing, especially the inlet manifold.

2) Ignition system. A weak spark can cause the symptoms you have. The easiest way of testing this is to "borrow" components off a known good runner. I'd be whipping the coil, leads and dizzy off and testing. It's unlikely to be the plugs unless you haven't gapped them. Timing in my experience is rarely the problem, the 4 pot petrol lumps are very tolerant of the timing being some way out. If it's as bad as you say when under load I'd expect the idle to be crap too.

Timing, plug leads and plugs would be my next to check items....

timing checked several times leads swapped...

Coil or condenser would be my guess

condensors new, could try a new coil but wouldnt the coil either be **** or not?

 Forgot to update this, problem solved, turns out the brand new points or condensor (allmakes 4x4} was problem, a electronic kit from simmon bbc cured the problem. Touch wood I will now have a strong n reliable ignition system for a while. Thanks all 

 yes really cant fault it, starts better than it has in a long time,was simple to fit and even with the vacume gubbins taken out of dizzy to fit it in,it runs great throughout the rev range,if I brought it 5 years ago it could of paid for itself how much ive wasted on cheap naff points n condensors, im a happy chappy