running rough (t40'd engine)

[SRlew]

right cars running rough lately, its like jumping at say about 2700 rpm then again at 3500rpm, then after 4000 its ok,

iv had the carbs balanced by a mate, and iv put new leads and plugs on.

dont want to go get them set up and find its still doing it as it'll be a waste of ???'s so what does it sound like? could it be the carbs?
it never used to do it

cheers lew

[Adam]

Hmm, did it just start doing it without you touching/changing anything?

[SRlew]

yeh it did.

like i went for a drive it was fine, then later on in the day there was a slight change. then it just got worse, feels like its worse when warm aswell, i think any way

[tom reid]

What type of springs/cups do you have between the carbs and manifold, they might need adjusting, sounds like an airleak.
hth

[SRlew]

ah right not thought of that tbh, im using those rubber washers with the brass cups, will go check that as they are new one i put on etc

[Adam]

Make sure the gap is correct in between the cups.

[SRlew]

right think i need to do up the bottom row a little by the looks of things, will let you know how i get on

[SRlew]

right then, i checked the carbs are done up corectly etc, done them up a touch more aswell, so there defo on tight enough etc, inlet manifold is on nice and tight and is a new gasket.

a mate said his was doing this when his was taking in air from between the carb and inlet, his is a 32/34,

any other suggestions?
cheers lew

[garyc]

Have you taken all the jets out an dchecked they are not blocked, check the carb filters too while your at it.

Did you take the carbs off and examine the rubber O ring thingies? I've seen them split before.

[Driver]

take carbs off and check everything is as it should be, ie no cracks or perished seals etc

[SRlew]

well the O rings between the carbs and inlet are brand new so wouldnt have thought theyd be cracked, never had a carb apart before, where are the jets? easy to take out?

carb filters?
but noticed the other day that there is a bit of petrol on top of the left hand side carb??

i floored it yesterday in 3rd and it went like s**t low down rpm then as the revs got a bit higher i actually felt it not pulling etc

[Adam]

The main and idle jets are under the covers on top of the carbs.
They unscrew.

Perhaps one of the air correctors has got blocked or something.

[garyc]

here is an exploded diagram http://www.carburetion.com/diags/45DCOEDiaginfo.asp

[tom reid]

Have a good spray round all the carb connections and the inlet manifold, still sounds like an air leak.

[SRlew]

well i had a spray around and it didnt do any thing, might give it another try, i couldnt realy get to the bottom of the carbs so will try there again.