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View Full Version : dodgy running 1.2 carb



jimbob-mcgrew
12-02-09, 09:50 PM
ok, where do i start...

*when cold*

it fires up straight away, but wont idle unless the throttles a quarter to half ish on (too little or too much and it dies), and the choke has to be moved in and out on a rotation every 20 or so seconds to compensate for the up and down erratic running to keep it alive untill its had a chance to warm a bit. it can splutter hefty when it feels like it. once its warmed and i think its running ok and drive off, half the time when i come to stop, the ignition lights come on right before it conks out, starting after that sometimes takes a bit of cranking.

*when warm*

sometimes takes quite a while to start, despite the fact that it idles and runs fine. idle rpm is prety high, id say around 1050-1100 RPM judging by the sound.

-----------------------

the idle needs turning down, but i just know its gonna make the car an apsolute bast4rd to warm up, let alone drive when cold.

i slackened off an exhaust clamp and re-positioned the rear silence in a much better spot. i cleaned the inside of the airbox and made sure the filter was clean, then cleared out a whole load of creamy gunk from the airbox breather hose (pipe was thick with it), gave the carb a clean, and gave the outer carb linkages a good spray of wd40, plus re-set the choke cable, however i think it was acceptable how it was.

it seems to go a hell of alot better now. like +10 horse better! :cool:
but im still having those running probs at cold, and the high rpm when warm. i wanted to get inside the dizzy cap to check the contacts and the rotor arm, but both the screws are corroded to sh1t, so im gonna have to work round that before i can see that side of it.

i dont have the tools to check the timing :tard:
any idea's as to what it could be ?

^ bloody hell thats a big post :eek:

craig green
12-02-09, 09:54 PM
Sounds like carb icing to me......

Cold inlet air, freezing within carb. Waiting for spring costs zero.
Is the hot air feed off the exh manifold still inplace?

Sloth
12-02-09, 10:04 PM
that/\or, its got a worn spindle or and air leak. id say get a good used carb and get it set up on a hc machine.

jimbob-mcgrew
12-02-09, 10:33 PM
yeh hot air feed is in place, how does that flap bloody work ? i had a look at it while i was there, i couldnt get it ?, it just flaps about by iself as i can tell.

as far an air leak.. hmm, the large circular cutout in the base of the airbox is slightly deformed where it mates to the carb gasket, any cause for concern ?

whats a worn spindle ? lol

EDIT : i should mention its on 92k and its had a hard life, has been stolen and ragged atleast once lol

jimbob-mcgrew
13-02-09, 08:59 PM
had a fiddle today. tweaked a few carb settings, managed to get the rpm down a few hundred and running more comfortably. it responds better to the choke now, and doesnt seem to die after 30 seconds running, plus it doesnt over-run like a carbon caked engine when switched off, just shuts down :thumb: AW06 reccomended to get a hacksaw on the screw heads of the dizzy, which is a sound plan, so i can get a flathead on them and screw them out to investigate. still havent given it a proper cold test as the weather was warmer today, but it drives much nicer. needs a good thrashing down the motorway next to clear it out.