Rough running

[nodbe]

Hi Guys,

My S4 ( on webers ) will not rev above 4000 it just coughs, spits and misses.

It has lumenition and is on NGK 7ES plugs.

Anyone got any suggestions please?

[nebogipfel]

Isn't this the third time you have asked the same question?

You didn't respond to the previous suggestions ...

[nodbe]

Yes. Didn't find the first post so did it again!

But can't see any responses???

[Orsom Weels]

Yes. Didn't find the first post so did it again!

But can't see any responses???

Shouldn't be too difficult to find your own posts

Try here elan-f14/wont-rev-above-4000-t26077.html

[Matt Elan]

Have you changed the plugs for a new set? first (and cheapest) port of call.....

[ericbushby]

In order to seperate ignition or fuel try it under load, say uphill in third, and again revved in neutral. The carbs will be using different jets. If it still occurs at the same point the I would suspect ignition or timing. Please report back so that we can think again and please always report back when you have success so that we can all learn a little more.
I am still a beginner but these are my first thoughts.
Best of luck
Eric in Burnley
1967 S3SE Type 45 (running quite well)

[billwill]

Since you owned it has it ever run properly before?
What did you do just before it stopped running properly?

It could be almost anything from that description, from blocked jets, faulty float valves, plugged accelerator pump, ignition timing or even (if you have had the timing chain off) incorrect valve timing.


See also your other topic.
post171874.html#p171874

[toomspj]

I had same problem with my Sprint - particularly when it got warm. I simply changed the coil (used a Lucas sports one) and it was immediately perfect. I have Lumenition on it which has been there since 1990.

If I were in your position I would also look at changing dist cap and rotor arm.

All these things are cheap to do. Messing with carbs is everybody's first prot of call and normally just screws things up further.

If you think it could be fuel related (which would be that it doesn't sustain high revs) then check that there are no air leaks on the inlet to the fuel pump and replace fuel filter if you have one.

Paul

[bast0n]

Nodbe

Long shot but it happened to me in France - just would not hold high revs. Reason - filler cap not letting air into the tank fast enough!! Loosened cap - got home and refurbished the cap - problem solved.

[Chancer]

Rev limiter type rotor arm????

[nodbe]

Hi Guys,

My S4 ( on webers ) will not rev above 4000 it just coughs, spits and misses.

It has lumenition and is on NGK 7ES plugs.

Anyone got any suggestions please?

I've changed the plugs from 6ES to 7ES !!

Much better but probably need rolling road/dyno tune ( need to save up for this!! ).

Thanks for all the help guys.

[richardcox_lotus]

David - how on earth did you identify that was the cause ??? (Something that would never occur to me !)

Regards
Richard