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Bumpy starting.

edwin

Enthusiast
Messages
833
Location
Lichfield
Hi all. Ronnie has developed a bumpy starting routine. When cold, add choke , it starts, but there is the bumpiness of one cylinder not firing, which goes very quickly as all cylinders start working. After that, the engine works very well.
I have had new points, capacitor, I have not looked at the plugs, did not have time. No smoke/steam from the exhaust, so no apparent water leak, no oil burning. Any ideas please for things to look for to sort this.
 
It sounds like the one cylinder that's not firing properly is building up compression before it starts to run properly. This is sometimes caused by fuel washing the oil film from the cylinder wall, thereby reducing the compression, thus preventing it from firing. After a few seconds the oil pressure restores the film and the car runs properly.

Just an idea, based on your explanation.
 
It is unlikely to be anything serious. Probably just ignition on one of the cylinders is getting a bit weak. A bad connection in one of the ignition leads maybe or a dirty distributor cap. Could be the plug it it's dirty. Might be compression - you can do a check for that but if it's running fine otherwise it's worth looking into but not an immediate issue..
 
I suppose you have the standard Zenith 28IF carburettor. There is a rod at the side that links choke flap with fast idle linkage. This rod can be adjusted by a set screw on the choke operating plate. Mark its position in relationship to the setscrew and try loosening this screw and moving the rod downwards a fraction - like 1-2mm - and see if it makes things better or not.
 
Hi all. Ronnie has developed a bumpy starting routine. When cold, add choke , it starts, but there is the bumpiness of one cylinder not firing, which goes very quickly as all cylinders start working. After that, the engine works very well.
I have had new points, capacitor, I have not looked at the plugs, did not have time. No smoke/steam from the exhaust, so no apparent water leak, no oil burning. Any ideas please for things to look for to sort this.
Hi Edwin... May I suggest a process of elimination, stating with the easier options? As Ronnie is starting, there's fuel there, so most likely an electrical/ignition issue. How about fitting new ignition leads? Clean the distributor cap at the same time. Easy swap, relatively low cost. New spark plugs next on the list....
 
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