I found my Volvo to be running at too high throttle during idling after gotten it back from the workshop last week. It is obvious when I stopped the car at junction or parked the car before turning off the key. Way too high RPM (although I couldn’t know the RPM value as my tachometer is faulty), I could hear the sound of the engine revving as if I was pressing the gas pedal. If I shifted into gear 1 and let go the clutch pedal, I don’t even have to press the glass pedal to keep the car moving forward. This is how much the idling RPM of the car, which is no good to the engine, sound and petrol consumption.
Googled online and I thought I found the screw where idling adjustment is. When reached home from work, immediately I tried finding the screw and wanted to adjust the idling speed of the engine. No, I couldn’t find the screw that I thought where it should be. Instead, I saw another screw which seems to be connected to the throttle. So, got a flat head screwdriver in hand, I just tried turning it loose.
Yes! The revving of the engine became softer and slower. That is definitely the idling adjustment screw.
I turned the screw all the way till very loose, and the engine still running not dying. I then tighten it a little, and I use a paper cup piece to insert in between the screw and the throttle to make sure that they still get in contact with each other and my screw is not all the way loose till too far up.
The eengine was hot when I adjusted the idling screw, which is the correct way to do, as if the engine is still cold, you will not get it right. Still, I will have to try starting the car tomorrow to see if it can still run by itself at idling during cold start.
On the note: the previous owner has removed the choke cable from the carburetor, I am not sure why. He said it is not needed.