Miss fire

Hi
My bus has developed a miss fire and won’t tick over when warm if I rev it hard it seems to clear it then it ticks over could it be the automatic choke getting stuck or coming on?
I have changed the plugs, coil,points and the HT leads.
I am suspicious it’s the carb/choke?

 

Sounds like the float or needle valve could be bad and fuel is flooding the engine.

 

Almost certainly electrical - it seems that the only thing that you haven't changed is the condenser - and that is the one part that could cause the symptoms you describe - also the dizzy cap would cause a consistent misfire but that would get worse when revved .

 

Usually the failure to tick over when warm is the wire falls off the shutoff solenoid.
But because it clears after revving it, it does sound like over fuelling.

When you drive it at 30-40mph in 4th gear, is it hesitant - more likely fuel related.

Intermittent ignition failures usually result in pops and bangs from the exhaust.
Over fuelling it just burbles and stutters.
And stinks of petrol.

The fuel metering valve in the carb float chamber does get dirty and stick open.

 

Update.
I have fitted electronic ignition problem solved my bus has never run so smoothly

 

Probably the condenser starting to fail as that was the only thing I didn’t replace

 

Yes, condensers have a limited life span.
Unfortunately so do electronic ignition units.

Sometimes the problem lies with electrical problems round the coil which damage the condenser, the same overvoltage spikes can damage electronic units.
If you changed the coil then you probably eliminated the root cause of the problem.