My 510 (1981) has been idling irratically for years. It is ok when cold, but at operating temp the idle varies from 1100 to 1400rpm. When at 1400 I could bring it down by tapping the acelerator. Recently the idle has gone up to 2100 when warm and I can't get it down. Idle adjustment screw doesn't do anything, not does tapping the accelerator. Can anyone tell me the cause and solution? Thank you.

If idle speed increases as engine temperature rises, the problem could be a worn throttle shaft causing a vaccuum leak. Given the problem has been occurring for a long time it probably time for a carby rebuild.

It's common for the late 70s automatic chokes to get stuck, and choked with crap.

You are going to have to learn how to tell when the choke is on and when it is off.

The choke unit may need adjusting/cleaning or replacing. If it's the original carby, then shaft wear is unlikely. Shaftwear is a common problem on older DCOE webers.

Pull the air filter off, and look to see that the butterflies are closing properly. Check for hoses that have fallen off, this may be giving the engine more air than it expects.

Go to the wrecking yard and get a second carby, shouldn't cost too much, and may come in handy as a spare. Try and get a carby rebuild kit (to get new gaskets) and rebuild the carby. Clean everything up with a can of carby cleaner. Check that the automatic choke works as expected.

If you don't understand what I'm talking about, then it's time you got together some friends that are mechanically minded, or you sit down and read a manual that explains how your particular carby works.

I had a Galant that idled too high once. I couldn't work out why! I changed mixtures, turned screws, replaced springs, everything!

Then one day I was looking for something under the seat and noticed the carpet was wedged under the accelerator pedal!


Well, I thou ght it was funny...

I'd love to see some photo's of your 510.