1.9dg Auto - idle speed too fast when in neutral or park.

[djswain1]

I checked & adjusted the timing today it was a bit too far advanced but adjusting it has not made any noticeable difference. I've already checked for air leaks by spraying brake cleaner around the carb base and vacuum hoses etc when running with no noticeable change in engine note/rpm.

[jamesakers]

At the weekend I fitted the test carb which I rebuilt. All new gaskets and no air leaks. I followed the Bromyard instructions for the initial setup and the choke flap appeared to be working correctly.

Like yours, the revs would not drop from about 1500 RPM even when backing off the idle screw so it is just touching the plate.

I went back out this evening to make sure the fast idle screw was coming completely off the steps.

Here's the view from above:



Looked fine but when I took a picture from below the fast idle screw was still on the steps:



This is how it should be when the engine is warmed up, completely off the steps:



A video showing how it should come off the last step: https://www.youtube.com/watch?v=rzslTQ0rd5E

The warm idle screw was in this position (just touching the plate):



Problem: The warm idle screw is screwed in too much preventing the fast idle screw from coming off the last step.

I unscrewed the warm idle screw completely, activated the throttle so the fast idle screw came off the last step then restarted the engine which idled at 800 RPM. I then screwed the warm idle screw back in till it reached 950 RPM.

Have a look and see if the same thing is happening on yours.

[djswain1]

Thanks jamesakers I will check it next time I get chance.

[Banzai]

Thanks James.
I followed your rebuild blog and the engine is running beautifully.
But I could not set the idle speed!
This fixed it for me.
Top man