Background:
Just installed a new intake manifold gasket.
While there, adjusted the valve lash on my 84 Elky per shop manual specs-but only 1/2 turn instead of a full.
I did manage to break a Thermal Vacuum Switch that the Cannister Purge Valve Plugs into--still trying to find a replacement.

Set the timing 6 Degrees BTDC in drive, engine warm with 4 pin disconnected.

Adjusted low idle with set screw next to linkage. Seems to run great, but
it won't quit--it diesels FOREVER...unplugged the 4 pin to get it to stop.

What now?

You could be experiencing a lean condition or the idle is set too high or the timing is set wrong.

How fast is it idling? Are you sure you don't have a vacumn leak. Do you have a AC idle compensator solenoid and is it adjusted properly? Engines diesel because the butterflys are open too far at idle.

The problem of runing after the key is turned off usually means that the combustion chamber and valves have a buildup of carbon. I have had good success with "Seafoam" an oil product that you pour down the carb. It cleans the carbon.
Also to stop an engine that is dieseling, just leave the trans in drive and turn off the key.

Also to stop an engine that is dieseling, just leave the trans in drive and turn off the key.
and people think you have a standard!! :D

another good, but cheap way to get the carbon build up out is to slowly pour a pop can or bottle full of water into the carb while taching the engine up a bit, soda pop is cheaper than Sea Foam and you can drink the pop :-) before you start, water's even cheaper unless you use Evian because you gotta have the high dollar stuff for your high dollar elky :lol:

Why did you replace the intake gaskets? (hope you replaced both of them.) Did this problem exist before replacing the gaskets?? Are you sure you have no vacumn leaks, could have leak on the valley side. To check the head side, spray some wd-40 along the gasket line between the head and intake, if engine speeds up tighten up the intake bolts. Make sure all the hoses are connected properly, and/or not cracked. Is the pvc valve working properly? Unplug the idle compensator and see if the problem goes away. If it does adjust it according to the veci label.
Seafoam is an excellant product and mat be worth trying if dieseling has been a past problem.

Most of the time, dieseling is caused by the idle set too fast. But, since you recently replaced the intake gasket, I would suspect a vacuum leak, especially if it did not diesel before the gasket replacement.

Thanks for all the responses.

I know I have a vacuum leak as stated in my initial post that I broke off the Thermal Vacuum Switch connected to the Canister Purge Valve. I am not sure how detramental this is? I am awaiting a new one (today hopefully)

To answer some questions: I changed the Intake Mani Gaskets due to a water leak--ever seen cream colored oil?--and that is all taken care of.

The car ran fine after the job, but it wasn't until I set the timing to the specs that the carb problem arose. I think I have the idle too rich because the carb keeps backfiring and a nice cloud of vapor will gather and seep out of the air cleaner after sitting idle for a couple of minutes. Should I get someone deft at adjusting a QuadraJet to go at it?

Thanks again!!

I would not spend any money on it until the vacuum problem is resolved. To find out if the broken thermal vacuum switch is causing the problem, simply plug the vacuum port at the carb that goes to the thermal vacuum switch. Then run the engine to see if the problem is gone. If not, it is something else.

To learn how to make the final adjustments on a Qjet with the engine running, go to www.recarbo.com and read their instructions for adjusting a Qjet (E4ME).

I replaced the thermal vacuum switch and double checked all my lines and hoses and gave her a crank and she runs! Very well and quietly in fact, but has absolutely no pickup--just slow acceleration (sounds like timing). If I idle up with the slow idle screw, she starts dieseling again when I turn her off.

Does my carb need more tweaking by someone who knows?

Thanks for any help!!

Slow acceleration, when the engine seems to run fine, could be a clogged catalytic converter. Have it tested at a muffler shop. When mine clogged, it ran fine but did not have enough acceleration to merge with moving traffic.

Thanks for all the input.

I had a ASE Tech come over to my place and after checking the carb, said "let's set the timing to the timing tab behind the water pump instead of the after-market bolt on."

Runs better than ever....

Thanks again.