Spluttering at speed

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Sidney'61
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Spluttering at speed

Post by Sidney'61 »

Hi,
I was driving down the motorway the other day when the car started to splutter and jerk, it continued running and got me to my destination but any speed above about 40 it was very jerky, it seemed to run fine afterwards for a lowspeed run to the shops though, I know that the timing chain rattles as it has for a while so is this problem possibly timing related?

Thanks,
Andy :)
Andy W____________1961 2-door 948cc (Sidney)_____________1963 2-door 1275cc (Emily)_______

PSL184
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Re: Spluttering at speed

Post by PSL184 »

Sounds like it could be timing related. Check the base plate of the dizy and make sure its not sloping around all over the place...
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charlie_morris_minor
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Re: Spluttering at speed

Post by charlie_morris_minor »

if it is not timing related check that the fuel pump is delivering the correct amount of fuel, it might not be delivering enough to keep the engine going at the higher revs on the motorway
bpr81a
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Re: Spluttering at speed

Post by bpr81a »

Completely gunged up Air filter game me those symptoms

Jon Rocke
bmcecosse
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Re: Spluttering at speed

Post by bmcecosse »

Yes - as others have suggested - could be fuel starvation - do a fuel pump test by timing how long to pump a pint into a container. Should do it in under a minute. If not - fuel filter blocked? Pump points needing adjusted? Pipe crushed/collapsed? Pipe blocked with rust/gunge? If the pump is ok then check if the carb piston rises and falls ok. Or of course - it could be ignition related - timing perhaps not advancing/points gap not right. It won't be anything to do with the timing chain. Could be dodgy coil!!! If all else fails - try another.
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LouiseM
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Re: Spluttering at speed

Post by LouiseM »

bmcecosse wrote:Could be dodgy coil!!!
Could well be. I had exactly the same symptoms when the coil packed up - a replacement sorted the problem.


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Neil MG
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Re: Spluttering at speed

Post by Neil MG »

Two more suggestions:

Little pipe between carb. float chamber and jet partially blocked by an old "O" ring at float chamber.

Vacuum in fuel tank due to cap not venting.
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MarkyB
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Re: Spluttering at speed

Post by MarkyB »

I'd start with a good service, points, plugs,air filter and tappets.
I like Roys idea of checking the pump flow as it's quick and easy, needs only a screw driver and a milk bottle, so a good starting point.
It doesn't eliminate all the fuel system, there is still the carb itself of course.
The colour of the plugs might be revealing after a run where it's been struggling.

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chrisryder
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Re: Spluttering at speed

Post by chrisryder »

bmcecosse wrote:Could be dodgy coil!!! If all else fails - try another.
Blimey, i never thought i'd see the day! :lol:

Andy, does it still have points and condenser, or has it got electronic ignition fitted? I had a similar problem when a condenser packed up. It very rapidly got worse and worse until it was undriveable!
bmcecosse
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Re: Spluttering at speed

Post by bmcecosse »

I wasn't really suggesting the coil......you lads obviously don't understand sarcasm..... It may however be the CONNECTIONS at the coil - disturbing these when fitting a new coil often fixes the problem. And yes - it could very well be condenser packing up.
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Sidney'61
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Re: Spluttering at speed

Post by Sidney'61 »

I found a spare condenser today and changed it, went for a quick run and it hit 70 easily on the dual carriageway with no troubles. I hope thats the problem cured, I'll have to see if it's still ok on a long run as it seemed to get worse on long journeys before. Out of interest, how does a dodgy condenser cause this problem? I thought they just either worked or didn't :roll:
Andy W____________1961 2-door 948cc (Sidney)_____________1963 2-door 1275cc (Emily)_______

linearaudio

Re: Spluttering at speed

Post by linearaudio »

Whilst you had your head under her hood, did you check the points gap? Worth checking! And if you suspect it was the condensor, it would be a good plan to run a bit of fine emery paper between the points as they will have started "burning" if the condensor was failing. Speed related reason?? At 1500/2000 RPM you may still be getting a moderate spark. At twice that speed, and under load, which will tend to quench a weak spark anyway,a dodgy condensor will play havoc!
bmcecosse
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Re: Spluttering at speed

Post by bmcecosse »

Coils either work - or not..... The condenser however deteriorates with time - it keeps on making sparks - but weaker and weaker......
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