Hi 

Whilst driving the other day my car started misfiring and cut out I was then unable to get it start for some time and when It did there was big smoke plume it ran for little n cut out again. Any ideas what may cause this ? Many thanks rory 

My first thought was coil breaking down when hot. Post what engine and ignition system you have.

Hi got the 2l pint engine on a webber 28/32 carb. It's got the original mannual ignition from the key on it. 

Could be the choke jamming on if it uses water temp to open/close?

If there was/is a problem with the choke giving a rich mixture then you should have lots of smoke just before it cuts out as the engine drowns. If there is the opposite problem, i.e. a fuel supply problem (blocked jet, blocked line, fuel pump failing when hot etc) then after turning over and not starting, whip out a plug and see if its wet with fuel. If it's dry then fuel supply could be an issue. However, by the sound of it, you get smoke when its finally starts, probably not a supply problem, but could look at plug anyway. Also when it turns over and doesn't start you could whip out a plug and with the lead attached check if there is a spark when the outer part is touched to earth with the engine being turned over (you need two peaple for this). You need to see a really good spark, because when the plug is in situ and under compression a spark is harder to produce, so a failing coil could produce a spark, but not at enough voltage to work in situ.

Edited May 27, 20224 yr by Sparepart
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It starts cold and runs for a few minutes before splitting and then misfiring and stalling. Does this sound more like choke or a coil ? 

 

Reagrds 

Rory 

Sounds more like choke to me.

But the other carb problem could be sticking needle valve in the float chamber allowing the fuel level to get too high.

The tiniest bit of muck or residue from old fuel can make a needle valve stick. It needs to go up and down with virtually no pressure from the float or your finger. Get a rebuild kit and change it if you are unsure if it is sticking or not. Personally I would just swap it for a new one and then you have ruled it out of the equation. Rebuild kits are not expensive 

Take off the air filter. When cold you should see the choke butterfly is flat across the main inlet tube. As the engine warms up the butterfly should rotate and open up the inlet, eventually becoming almost vertical, fully opening the inlet. If this does not happen then the fuel/air mixture will gradually become too rich as the engine warms causing rough running and eventually the engine stalls, usually with a strong smell of petrol in the engine bay.