[medic455]

So found outt that the daughters 96 Sierra has been, as she puts it running a bit funny for a while now. It starts fine and idles at about 1500rpm but as it warms up this goes up to about 2000 rpm and stays there other than that it runs fine but a bit rich, following the advice on here I checked and unblocked the water pipes to the choke but this has not changed anything, so where do I look next ?

[Marko_SJ]

medic455 wrote:

So found outt that the daughters 96 Sierra has been, as she puts it running a bit funny for a while now. It starts fine and idles at about 1500rpm but as it warms up this goes up to about 2000 rpm and stays there other than that it runs fine but a bit rich, following the advice on here I checked and unblocked the water pipes to the choke but this has not changed anything, so where do I look next ?

Does it do this as it warms up, or after you use the throttle?

Also, have you observed what the choke is doing with the carb hat off. I'm sure you have.

Mine does similar after you press the throttle. Its to do with the linkage from the throttle linkage to the choke butterfly. I think the springs flogged out, and needs changing. Still thinking about how to make a dodgy sierra driver fix (without wiring the choke).

[alien]

The auto choke is prone to failure (the wax buggers up) - when i had the old 1.3 carby and the choke went, it'd also backfire a little if i engine braked, particularly on a downhill.