Idle Problem Solved
 

Wow, I solved my irregular idle problem. My 1983 911sc would idle high when warm would oscillate and surge when cold. Then sometimes would be right on where it should be. I thought the problem was the fuel system until the ignition distributor started to make noises and the idling got worse. I could detect a pattern the distributor grumblings and a surge in the engine idle. It sounded like something had got loose in the distributor and was binding with something in advance chamber of the distributor. I took the distributor apart and found a spring loose from the mechanical advance weights. I hooked it back up, re-install and the idle problem is gone! It is "ROCK STEADY" idle now! After re-install of distributor I had to adjust the ignition timing, it seems to me the last time it was adjusted it was influence by the particular position if the loose mechanical weight. I summary I think the my idle surges and irregular idle, was caused by timing advance issues-the free floating mechanical advance weight.

The next thing is where can I get the little plastic bushings used for mounting the mechanical advance springs in the distributor? Mine are gone, I ended up pinching the springs hooks to make sure they stay on.

sal,

Thanks for posting this.

Too often we are lead astray by symptoms that indicate one system (fuel) where all systems need to be considered.

Best,
Grady

Dizzy parts
 

I just recently spent weeks phoning anybody and everybody to find the samething. I finally found out that no service parts are available. You may find a rebuilt on the self $$$$ or your next best bet is a used unit off the board and make one out of two. This is the route I went it is a heck of alot easier on your wallet.