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Hi all.
I have a 1256cc HA van and I cannot get it to run correctly.
It has a powerspark electronic ignition kit, new plugs, new dizzy cap, new fuel filter and pipes. Timing 9 deg BTDC.
What happens is it starts well hot or cold, and idles reasonably well. However when driving and I put my foot down it's kind of "jerky" progress as if it's starved of fuel.
It has a Weber ICT 32 carb so I set the base settings and tried to get it to run a little better. Still the same. But when I put my foot down and pull the choke out about 1/4 of an inch, it runs perfectly.
So....I stripped the carb, cleaned it all and the made sure all jets were clean and clear, and checked the diaphragm. All good. I cleaned the inlet filter and renewed my main fuel filter for peace of mind. Put carb back to base sttings, adjusted mixture and idle, no different!!! Pull out the choke and away it goes smoothly. I have a spare ICT32 so I removed the mixture screw from it and replaced my original with it. I was pleased to see some doughnut had turned the screw in a little too far to "seat" it and it had a small mark on it, so surely my perfect replacement would do the job? Nope.
So I'm still chugging away unless I pull out the choke.
I've ordered a rebuild kit for the carb but I can't help but think I'll be wasting my time.
Can anyone shed any light on this please?

So, if it runs with choke but not without, it is too lean.

Lean = too much air. So, could it be coming from somewhere else? Try spraying around the intake manifold with WD40 or starter fluid - it the engine speed changes, you have found your leak.

When I put my Midget (sorry to use the MG word here ) I hadn't properly tightened my intake manifold - so, it would start and run fine but then as it warmed up the metal would expand and open up a gap. Took forever to sort - including being stranded more than once. The clue was when I put my hand over the air intake (restricting flow) and it suddenly ran perfectly.

So, it might be another source than the carb. Can you tape off part of the intake and see what happens?

Thanks for your reply.
I've tried the leak test.... nothing. Revs stayed constant. I sprayed carb cleaner and just to make sure I later tried WD40 and all stayed the same.
I did notice my mixture screw will make the car "hunt" when I screw it inwards but does basically nothing when I screw outwards. Even to the point its completely unscrewed.

WhiteVanMan wrote:Thanks for your reply.
I've tried the leak test.... nothing. Revs stayed constant. I sprayed carb cleaner and just to make sure I later tried WD40 and all stayed the same.
I did notice my mixture screw will make the car "hunt" when I screw it inwards but does basically nothing when I screw outwards. Even to the point its completely unscrewed.

can't help at all with webers. Can you try to block off part of the air intake just to see if it is lean?

would this help?

http://www.redlineweber.com/html/Tech/d ... ical_i.htm

Inlet manifolds can occasionally become porous and allow air in. Does the mixture screw have an o ring or seal missing? Is it loose in the threads. If the car has a servo is the vacum hose sound. What do the plugs look like? Pale or sooty?

Peter

Thanks jpsmit. I think I've read every one of those weber pages

hbpeter. This is the mpost frustrating part, if I took a photo of my spark plugs you'd think I'd stolen the photo from the Haynes manual in the "running perfectly" section. They are a beautiful tan colour.

I just don't get it.

I set the float height today and made sure the inlet manifold was tight, run the car and sprayed carb cleaner all over the inlet manifold, no increase or decrease in revs at all. I'm at a complete loss. The only thing I can think of is fuel pump or the powerspark electronic ignition is playing up, but surely neither of those would explain the car running perfectly on a very slight application of the choke? I did notice on yet another test run that the longer I drove the car the worse the "kangarooing" became when applying throttle.

I have my first show of the year coming up on April 25th. It's a 27 mile drive and I have a feeling I won't be going.

Is the carb jetted corecctly, has it a too small main jet? Dont know what it should be. Did by a replacement Weber many moons ago that had the jets incorrectly fitted so that when you put your foot down it was blocking the fuel.

Peter

It's the standard carb for the car so it should be correct. "should"!!!

When I checked the timing again just now (still fine) I got a massive shock from either my cap or leads. It hurt
Would this cause the jerky progress? If so why would it improve with choke? This is a weird little car.

Dizzy caps can have hairline cracks which would cause poor running. is the engine earth strap in good condition and tight. No idea why the choke would make a difference.

Peter