Uphill struggle

Series 3 petrol 1994 109

Have a running problem with my landy Basically it runs fine most of the time except when I want to increase the revs on an uphill climb, it starts to splutter and totally lose power, finally cutting out.
Timing has been checked, new dizzy cap and leads fitted, earths checked.
Any help greatly appreciated as I may have missed the obvious.

The fault occurred after I changed the carb for the mot, this has since been replaced again but still the problem persists.

1994

lack of fuel i say ok on the flat but will want to pump it in on the hills check the filters

Fuel pick up pipe in tank got rust hole or broken at the top?

Have a look at the fuel pick up pipe by unscrewing the three? screws on the top and pulling out the pipe, on the bottom of the metal pipe should be a mesh filter which may be blocked as the holes are fine to start with.......some people throw this away and rely on a modern in line filter.
or the inlet side of the engine has a air leak and running lean.......

Sounds like your leaning out under load, backs up what everyone's said so far.
You say it happened after you replaced the carby, then the carby is the first place I'd be looking, are you sure its set up properly, also double check the mounts are tight for the carby and the manifold.
Which carb is it?.

Take the fuel inlet hose off the carb and crank the engine over. The fuel should flow nicely. If not then check the fuel pickup is not blocked. If that's O.K. check the condition of the pipes from the pickup to the lift pump, and check the unions. Try blowing through the pipework to check it's not blocked. If that's all O.K. then there's likely to be a problem with the lift pump.

If the fuel is flowing properly, but it's still having problems under load then check the float level is correct in the carb and that the valve which the float controls is opening properly.

Another possibility is that there could be a vacuum forming in the tank if the breather pipes are blocked.

Zeneth carbs have a known problem in the bodies warping, meaning the **** petrol every where doing very little for your ecconomy....
Sometimes, on mildluy warped bodies, cured by lowering the float height so theres less juice in the bowl o leak.
Of course come to a hill and tilt the carb, and low level will mean that the main jet is no longer sibmerged and you'll get fuel starvation.

Just another thing to look at.

Sniff the dipstick, if it stinks of petrol then you can suspect the lift pump seals, also oil level will be going up.
If this happened after playing with the carb, just have a quick look to see if you've accidently kinked a fuel pipe or got it trapped in somethink.

Thanks all for your comments.
Firstly 1975, whoops
A recap of what I have tried
1. replaced the replacement carb with another unit (zenith), though I have not stripped down the carbs as they were new.
2.in line fuel filter replaced, fuel lines blown through with compressed air, visual check on fuel pick up pipe.

I'll recheck the manifold and carb bolts as these have been undone in the past, along with the fuel pump. Also will check the breather pipes.
Anyone in the Plymouth area that could lend a hand over the weekend would be greaty appreciated, beer tokens would be available.

Please keep the advice coming

Might be worth looking at the spark plugs after a run as the colour and condition can tell you lots.........