13 replies to this topic

[annie34]

mayfair
1986


plugs 2 and 3 are sutted up 1 and 4 are o.k.
got really bad misfire.
any ideas


Thanks

[Big_Adam]

It;s the way the head/manifold is designed. Completely normal. If you really want to fix it then you'd need twin carbs or a different head.

[markaboot]

mayfair
1986


plugs 2 and 3 are sutted up 1 and 4 are o.k.
got really bad misfire.
any ideas


Thanks

miss fires probably from the sooted up plugs, the cause of this could be lots of things.
im no expert but i know that on my 1275 the 4th cylinder is sooted up and thats from a leaky valve seal.
thats assuming you have traced the misfire to one or both of these cylinders.

if not a miss fire is most likely, dodgy plugs, dodgy leads or a dodgy dizzy cap.
try running the engine and removing 1 lead at a time (careful not to get a belt). if it runs worse then thats not the problem cylinder and put the lead back, if it runs the the same you've found the cylinder with the missfire.


a temp fix for the miss fire might be just to wire brush the plugs, get them shiny again.

EDIT: or what he said above haha

Edited by markaboot, 14 February 2009 - 11:11 AM.

[Retro_10s]

Woah there, Ok. Ignore what the plugs are showing you at the moment (and put aside any suggestions of changing heads and carbs!) and concentrate on the misfire.

Have you changed any parts recently and where is the mis-fire occuring i.e. all the time or only at certain revs etc?

[annie34]

hi its missin all the time, plugs etc been changed about 3 times, just doing compretion test at mo.

[markaboot]

hi its missin all the time, plugs etc been changed about 3 times, just doing compretion test at mo.

plugs etc?

a full list of exactly what you've done would help people diagnose

[annie34]

sorry,
changed plugs, coil, dizzy cap,leads. its electronic ignition had module tested thats fine.

[Saxo-Fiesta-Mini]

could be the rotor arm or easier may be the needle needle needs cleaning on the carb

[annie34]

mmm thanks will try that, there is a small crack in the manifold do u think that may cause a problem?

[markaboot]

could be the rotor arm or easier may be the needle needle needs cleaning on the carb

yup sounds like same thing my 1098 is doing.
i've ruled out ignition and im looking at fueling now.
i suspect a blocked jet with mine because my float bowl was full of carp.
and it runs fine a low revs but soon as i open the throttle its *poop poop*.

dont mess with any carb settings tho. just clean it.

[annie34]

Hi,heres an update on my mini thats still playing up
today we have had compression checked thats o.k. , valve clearences checked and adjusted, and carb stripped and cleaned . The car runs lovely while stationary even when you blip the throttle.But still misfires when accelerating off down the road.Any ideas.

[Ethel]

Which manifold looks like it's cracked? It could be the problem, casting marks can look like cracks though. Try blocking off the vac advance.

[annie34]

Hi, its the exhaust manifold the lcb type.

[philc]

may be worth checking the timing and adjusting the mixture, also ive the carb a good service