2 litre A/C running rough

[mushroom]

It's been running rough for a while , but slowly getting worse and worse
Basically when it's cold, it sounds like it's misfiring, try and pull away on a hill and you have to floor the pedal to get 5 mph with it putt putt putting ( really handy going over busy junctions )
when it's warm it's semi - ok, fuel consumption seems to be up though
changed the spark plugs and the dizzy cap, thinking it could be the electrodes frigged or a cracked cap.
Next up is the HT leads and rotor arm unless someone says " I know, I had that very same problem and cured it with ...... "

coming round the m25 the other night with the pedal halfway down and not moving, the bus seemed to surge forward and then stop over and over again, almost like it's pulsating

failing all that, I guess it could be the carbs

thanks
mush

[DiscoDave]

just a guess maybe fuel filter! but just a guess

[corleone]

erm here's a few ideas, probably none of which will help but worth a go

try disconnecting the idle stabilising unit, mine was running rough and stalling when this was on its way out, just connect the two wires together.

vac advance working properly?

Another long shot is the inlet manifold gaskets - spray some light fluid around them when she's running - but when these went mine ran better cold than hot. good luck!

[Bensdad]

Had this problem myself in the old mans camper. Stripped the carb and blasted the jets/needles with compressed air... sorted.

[mushroom]

thanks for the replies, just spoken to toolsntat on the phone and he's given me some pointers to try too
now just got to find time to tinker

[Aidan]

These carbs are also known for airleaks on the spindles, lack of power, poor idle, crap fuel economy being typical symptons. Steve Shaw (Steveclub80-90) can rebuild them and then you have a flyer again.

[cumbriankeith]

There's potential for airleaks in quite a few places - like those already mentioned - also the rubber elbow and "T" peice on the balance pipe (takes inlet vacuum for the brake servo) they perish/crack and cause some of those symptom like that...

[mushroom]

Changed the fuel filter yesterday, didn't make any difference at all.
Checked the carbs and noticed that the left hand carb manifold is icing up when running. Any ideas why that can be ?
Bus runs fine down hills, but struggles up the smallest of inclines and usually have to resort to going down to 2nd gear with it popping and backfiring.
Checked the HT leads and tightened all the screw-in connections, could it be one of the leads breaking down under load ?
Next thing I'm changing is the leads and the rotor arm
process of elimination I guess

[mushroom]

right
changed the HT leads, rotor arm and a split elbow vacuum hose from the right hand inlet manifold, the one that connects to the balance pipe

and now it runs great, cheers everybody who added their tips