Carb Problem

[Guest johnboymac]

If I start my engine, the auto choke kicks in, the car idles for ten mins or so, then goes rough and splutters and dies. It can be kept running by hitting the throttle. however on checking the carb I can see that the butterfly is fully opened. after waiting 20mins for everything to cool, the valve closes and I can restart the car, it again idles for 10 mins then dies (and yes the butterfly is open again).

 

any ideas on this?

[Guest boggie]

Sounds like you have air leaking into the intake after the carbs somewhere. This means that things are OK with the choke on because the mixture is rich but once the choke is off the mixture entering the engine is too lean and is causing the problems you have. Also by pumping the throttle once the choke is off you are compensating for the lean mixture as the accellerator pump squirts neat fuel into the engine.

Check that you have no unplugged inlet take-off points (eg servo vacuum and vacuum advance etc), check for leaks around the manifold and gaskets too.

Good luck!

[Peter Bell]

Check your idle jet(s) are not blocked too.

Peter

[Guest johnboymac]

sometimes, I think ive spoken too soon. Drove it out of the garage, turned it off and left it for an hour. went I went to start it again, nothing - engine turns over on the starter, but its not firing at all. there is a spark at the coil, and fuel is pumping through the system, but otherwise....

any pointers as to where I should start, is it likely a blocked jet in the carb?

[Guest Simon M]

I had a similar problem.

I found the diaphram in the auto choke was split, so the vacuum could not hold the choke partially open- ie it was running too rich. Only a problem at tickover.

Once the engine was at full temperature the car was fine as the engine didn't need the choke.

Ford wanted to sell a complete assembly for ~£30 so I decided on a temporary fix & sealed the split with a petrol resistant flexible sealant- 6 months ago.. still going strong. Or you could try a scrappy for another diaphram.

 

HTH

Simon

[Guest johnboymac]

simon -

 

I stripped the carb and checked all diaphrams - the only one with a problem - (as you suggested, thanks!!) was the one in the autochoke, not a split, but a number of little ruptures all around it such that the far side of the casing had sooty marks where it had been leaking air\dirt. none of the parts shops seem to have a bit to sell (though one offered me a replacement carb at £235+vat - er no..). what was the petrol proof sealant you used, I might give it a try as a temp solution.

 

many thanks for the advice, John

[Longboarder]

Two alternative solutions are to remove the choke butterfly and start from cold with dabs of accelerator to richen the mixture till it runs OK or fit a manual choke cable.

 

Nigel

[Guest Simon M]

John

It was blue gasket sealant from Halfords, it's non setting.

My diaphram only had a pin hole in it so I was reasonably confident of a temporary cure. I applied the goo on the outside so that air pressure would hold it in place.

 

Simon