High Idle question

[Bearcuda]

Well, I changed the jets in my Barry Grant carb because my Charger had been running rich with all the around town driving I do. The smaller jets seemed to be ok, but a few times when I start it, the idle is high and won't come down until I put it in gear. This is similar to the problem I was having with the carb the car came with and an old holley I had laying around before I bought the Demon. Before , with the old carbs, it would idle high and then surge back and forth as I drove it. The Demon seemed to cure all of my woes and thats what has been on it for about 7 months now. Its only after I changed the jets that it is doing this now. Plus, its not all the time. Any clues?

[Bullitt-]

I don't know if this has to do with your issue but I was talking yesterday to our Mopar club president & he had problems getting his over-cammed 440 to idle, it would surge at idle. Ended up needing a heavier distributor mechanical advance spring.

[Oldschool]

Check the timing....        

[moparniac]

as OS said to check timing WHY did you change jets? on a hunch? post a pic of your BG carb....


 throtttle blade screw should be 1 1/2 turns  on the primary then  set timing... then lean/fatten it up from the idle mixture screws...... 

[Bearcuda]

as OS said to check timing WHY did you change jets? on a hunch? post a pic of your BG carb....


 throtttle blade screw should be 1 1/2 turns  on the primary then  set timing... then lean/fatten it up from the idle mixture screws...... 

Changed jets because it was running rich. I could tell by the way it ran, the plugs, and the soot around the bowl. It runs fine with the smaller jets and the idle is even a little more tame. Its just that upon starting, it has idled high a couple times until I put it in gear. Then its fine. Timing was set about 5 months ago. Don't think it would be out.

[moparniac]

I would still go back over and check all the basics. your throttle blades adjuster screws may be turned in too far causing the high idle and richness.... back out the adj screw and once it touches and go 1 1/2 more turns and make sure you are square on all your idle mixture screws and re check timing.... 

[moper]

I like Demons least of all. Interesting that teh jetting does not affect the idle. So I tihnk perhaps there is more to it than simple stuff. Did you wash the insides of the bowls before you ran it? If not, the chips are in the metering block. Every new Demon I work on now gets disassembled prior to install, and I check every passage and hole. There's a lot of hanging bits, and metallic schrapnel that gets hung up in the small passages.

[moparniac]

I have heard this from many also moper about bG's quality and a number of people have said they found metal shavings in there demons also.... what a joke 

[BacardiCBR]

I also have a Demon and I have also experienced high idle on start-up on occasion.  I began to notice that it was happening after the engine was warm and I shut it off and restart it within about 30-60 minutes.  Never does it on a cold start.  I've had it on the dyno and the A/F was fine.  The timing is fine.  I was going to check the float levels next as it acts like it has a lot of fuel to burn off before the idle settles down.