Starts but won't run

[Chris5360]

Ok so been getting some very helpful info on here lately as my car nears the end of it's resto, finally have a spark, and she starts, ran very lumpy and died.
So I cleaned the carbs out ( Webber 40s) it now starts runs smoothly and dies after about 10 secs then next try less and so on
Any tips please?

[ericbushby]

After it has stopped is there any fuel in the float chamber.
Remove the jet cover and then remove one of the large jet stacks. With a small torch you should see the fuel level. It should be approximately 25mm below the top of the float chamber or 41mm below the rim of the jet cover if that is easier to measure. A thin rod will do as a dipstick.
You do not need to put the jet stack back for testing. It is not used at low power.
Eric in Burnley
S3SE DHC

[Chris5360]

I'll have a look in a sec, to me it seams like it's fuel starvation, but the float height measures correct

[Chris5360]

Ok the bit where the needle goes in is empty when it dies

[Chris5360]

Ah ok seams to run with a few revs of accelerator but doesn't idle

[Chris5360]

I now seam to have some fuel coming from where th trumpets go in

[ericbushby]

After it stops is the fuel at the correct level in the float chamber?
Eric

[Chris5360]

Well it appears to have a decent amount of fuel in there, but it's hard to tell I would say it's 3/4 full, but in now thinkning it's something to do with the axle set up, as when I rev it high it keeps running but stalls as soon as I take my foot of the accelerator, but will run for about 10 seconds at idle when first started Almost at the end of the project and almost at the end of my rope

[ericbushby]

OK Chris, that is probably good enough and suggests that the problem is not fuel starvation.
Keith franck of sidedraft central who is an expert on Weber carburettors insists that the fuel level must be correct to within 1mm to achieve smooth running.
Have you removed and cleaned all the jets?
Next I would check the airflow balance between all four cylinders when running as slow as you can get and check the mixture using a Colortune plug.
Is the ignition timing correct?
Best of luck
Eric

[ericbushby]

Another thought.
As it runs for 10 seconds when started, that may be fuel from the accelerator pumps if you pumped the accelerator pedal to start it and at high revs it will be on the progression jets. So it may be that there is no fuel coming from the idling jets, but there are four of them. they can`t all be bunged up. It would start to misfire as you slowed it down if one was blocked.
Keep at it.
Eric

[richardcox_lotus]

You said you cleaned the carbs out, but can you advise how you did that ?

Also can you let us know if you have an electric fuel pump or are relying on the mechanical pump ?

Keep looking, you'll get there.

Regards
Richards

[Chris5360]

I stripped the carb jets out be used carb cleaner and an airline, I have blown all the jets through,
I haven't removed the distributor, so can't see how it's timing but will check it tomorrow anyway, I'll try every possible solution now to get her on the road, I blocked off the headlight vacuum just in case it was vacuume related.
It's on the mechanical fuel pump stil, frustrating thing was she ran perfect til I took her off the road 4 months ago !

[Chris5360]

Could it be a problem in the manifold gasket side of things possibly ?

[nmauduit]

Another thought.
As it runs for 10 seconds when started, that may be fuel from the accelerator pumps if you pumped the accelerator pedal to start it and at high revs it will be on the progression jets. So it may be that there is no fuel coming from the idling jets, but there are four of them. they can`t all be bunged up. It would start to misfire as you slowed it down if one was blocked.
Keep at it.
Eric

I'm on a carbs issue as well (not dizzy since runs smoothly on occasion), with not enough fuel flow to maintain chamber level : did you check that a fuel filter was not clogged somewhere along the line (including the mesh filter that is on the carbs themselves) ? Getting fuel directly to the carbs from a small pot located above the engine would help answering the fuel delivery issue (make sure you plug or direct to a safe place - not the coil or dizzy - the fuel that may be flowing from the pump while doing so), as a workaround if you see the fuel level is not correct when the engine stops as said above. A properly operating carb will have fuel level correct at all times.

The correct idling for 10 seconds is an important clue (please specify : throttle position and pumping or not, exact duration, smoothness ) ... what was found when cleaning the carbs as well.

For a quick check one may just fill up the fuel chambers with a bit of gasoline, but that is not as good as setting up a gravity feed - and one need to be cautious of backfiring consequences in case of overflowing the carbs (keep the filter bow in place)...

[Chris5360]

Right I solved it turned out to be the wire from the tacho to the coil, very strange would let it idle for 10 secs nicely or rev roughly for as long as I pressed the peddle,
Bypassed the wire as a end or my tether thing as I'd exhausted all carb possiblities and started on things like points gaps
Runs lovely now, on to he last two probs, my indicators dont flash, appears to, bypassing the flasher gets solid lights, but yet they worked this morning !
And the drivers window won't go all the way up at the mo
So hopefully on the road for the weekend