Idle speed?

[wolfgang]

Start up fine. Drive a for 20 mins or so and stop at lights and the engine sounds like it is running fast. Press down on the accelerator while in neutral and the engine returns to a correct sounding tick over. Is there an easy fix and why does the engine end up running fast. Pretty sure this is going to end up running too hot on a long journey.
Thanks

 

[creationblue]

Start up fine. Drive a for 20 mins or so and stop at lights and the engine sounds like it is running fast. Press down on the accelerator while in neutral and the engine returns to a correct sounding tick over. Is there an easy fix and why does the engine end up running fast. Pretty sure this is going to end up running too hot on a long journey.
Thanks

I used to attach a long Spring from the engine bay ceiling to the butterfly shaft to help it close when off throttle. Everything gets hot and expands and it may need a little help returning.