L-82 4Speed

I've already adjusted it to 700, just haven't driven it enough to tell if it helped. I will say that it took the gas better between shifts and after coasting and getting back on the gas when the idle was at 900. It feels like there is a slight delay when I hit the gas now.

leadfoot4

Yes, because if you lift off the throttle a little, when you shift, the engine is dropping down to 700 RPM, rather than 900 RPM. this would ne a normal reaction.

Also, something to consider is the formulation of gasoline has changed drastically since your car was new....and was calibrated by GM, to run on the (better) fuel that was readily available in 1979. You may need to compensate for that.

Just out of curiosity, what water temperature is the engine running? If it's running hot, due to a bad t'stat, or plugged radiator, that also could be contributing to your run-on.....

L-82 4Speed

Around 190. Most of the cooling system is new.

derekderek

Sending carb to Lars is a bad idea-under the conditions he specified. Sending the carb to Lars to get it rebuilt and returned to you is a much better idea...

JoeMinnesota

By delay do you mean hesitation? The engine stumbles? Could be a number of things. Idle speed is just one of them. Timing is another. Carb settings and mixture another. If it stumbles, may be a lean problem, etc.

L-82 4Speed

It's kind of hard to explain. No stumble or hesitation,the car still runs smooth and strong,it just feels like it doesn't respond to the pedal as quickly as before. I ordered a heat shield to help with the hot start isuue so I am going to adjust the mixture after I put that on.

L-82 4Speed

So,I installed the heat shield,set the timing at 35 degrees at maximum advance, adjusted the mixture with a vacuum guage and set the idle at 750. The car runs great and the dieseling is gone but it is still flooding on hot restarts. If I only park for a few minutes it starts right up,it only happens after being parked for about 30 minutes or more. It's not hard to start,it just idles really rough and will stall if I don't rev it and blows a gassy smelling cloud of smoke.
Would a 1/2" phenolic spacer help with this or does this sound like leaking well plugs? Any suggestions?

leadfoot4

Q-Jets were/are known for internal leaks. It's been a LONG time since I've worked on one, but there were a pair of soft metal "plugs" that were tapped into place on a pair of internal passages. Over time, these plugs have been known to come loose, and cause issues. Maybe this is what you're now experiencing.

7t9l82

The qjet does have several issues, if you aren't skilled in their operation you would be wise to send it to lars. I've used holley qjet replacement in the double pumper configuration and the throttle response Is fantastic. I don't like vacum secondaries because they are soggy and th qjet was called the Quadra bog by many. But someone like lars can set it up to run better than the factory ever wanted it to.I have a quick fuel hr750 which is a double pumper but I changed my intake,and went that route.

lars

Aw, man, Derek... you're a real kill-joy..! Here I was hoping to score a sweet hi perf 800 cfm Q-Jet..!

As Derek says, if you don't want to donate the carb to me in order to get rid of it, I can set it up to run very well... There's another guy over on the C3 General section who also wants to replace an L82 800 cfm Q-Jet with an aftermarket carb... I guess I'll go tell him it would be a good idea to give me that carb instead...

The early 1966 - 1968 Q-Jets had plug leakage issues, giving the Q-Jet the "leaky" reputation. It is extremely rare to see a '79 Q-Jet with any leaky plug problems - the plug design was fixed to make that a rare occurrence.

Lars

C3 4ME

My 79 L-82 4 speed also is slightly flooded out when it only sits for a short while when hot. An example would be a gas stop on a long drive on a hot day. It does start right up, but i get a little black smoke for a second or 2 until it clears itself out. It never does it when cold, and like I said, even hot it always starts right up. One of these days I'll get mine to Lars to get it perfected. I know he's the expert and would make mine run like new again.

lars

No e-mail received...

Lars

L-82 4Speed

I decided to go ahead and rebuild the carb. I have never rebuilt a carb so this is a learning experience for me. After taking it apart I noticed that the 2 plugs circled in red were leaking so I guess that is what was causing the problem. I resealed all of the plugs and now I'm waiting for that to cure so I can finish reassembling. Hope to have it running again tomorrow.