6 replies to this topic

[charlie]

how do I set the choke correctly.

I've set carb up:- mixture and idling. But now car splutters and tries to fire when starting up.
When it does eventually fire, I get loads of coughs and splutters once get engine to rev fully, everything seem ok. if i let go of accelerator pedal, engine either dies or splutters again.

To get the car to run I have to rev at 2500 ish, and keep it there for a couple of mins.

This happens whether i have the choke on slightly, middle or full. If i use no choke, the car wont start.

After the couple of mins at 2500rpm, the car runs better. Once the temperature gauge starts to register, the car runs perfectly on no choke.

How do I set the choke up correctly?

cheers,
Charlie

[Mini Man Sam]

Silly question time, the choke cable is attached to the carb isn't it, ie the retaining bolt done up. As far as I know there is nothing realy to set up. The cable pulls the lever connected to the choke flap which in turns restricts the flow of air into the carb. (unless SU carbs are different to other ones I have worked on). Ensure that the choke pull on the dash is fully in, check that the actuator on ther carb works freely and that it returns to the open position on its own, feed cable through hole in adjuster nut, pull tuaght and tighten nut.

[Guess-Works.com]

This does not sound like a choke issue, but one of the car needs a tuning, when you pull the choke cable it does two things, in stages, as you first start to pull the choke this richens the mixture level, and then as you continue to pull the choke a cam on the thottle is move to raise the idle ( this is the fast idle setting )

You say you have set the carb up, what sort of carb is it, and have you any pictures on how you've connected the cables and assemblies...

Mini Man Sam, yes SU's depending on what sort, work differently, there is no restriction of air flow, but rather an increase in fuel.

[Mini Man Sam]

OK, cheers GuessWorks. I stand corrected, (and now better informed). Sorry for the duff info Charlie. Hope you get it sorted.

[Leonard]

sounds like the fast idle isnt fast enough. if this is the case, you need to turn the screw on the throttle lever so that its closer to the cam on the choke mechanism.

[charlie]

my carb is a hif 44. all i have set is the mixture and idle speed, that is when my cold starting problems arose.

The car was running that rich when I bought it that I never needed choke. It was only when I checked what mpg I was getting (about 10) that I realised big problems, as soon
as I checked mixture, i found the cause:running mega mega rich. I had to turn the screw leaner bout 3 full turns to get it right.

I am now trying to get info about setting choke cable, ie how much free play there should be and thanks to this forum I've found out about fast idle. How do I set this up?

[Leonard]

look where you attach the choke cable. as this turns round, it will push against the head of a small bolt. this bolt is part of the throttle mechanism. when the choke opens further, it opens the throttle more. to increase the fast idle, unscrew the bolt a little bit, so its closer to the choke mechanism. sorry i dont have a diagram, but this is how it works on a hif44.