The other day I had an interesting "play time" with my Camaro. Just to note, I have had it about a month and I only know what I can see from the outside, about the moter. I Adjusted all the rockers (found out I have a solid cam!). I set them a .025 because I have no clue what cam I have....and I reset the idle mixtre and droped the primary float back down to the middle of the site glass and went to reset the idle speed. Well I have a Speed demon carb and got the idle mixture to what I think is about perfect, but when I went to set the idle speed I was just haveing a real hard time setting it and not loesing the mix. I got it to run at about 1000 rpm (idled before at 800). Then I decided to look on Spdded demons website and figured out I have an idol ease base....Its a 650 mechanical secondary. I belive that moveing the butterfly stop screws, I have lost the setting on the transfer slots, which may or may not be alowing the carb to get out of the idle circut. My question, Is ther any way to rest the butterflys with out pulling the carb, or do I have to? I will say that between the rocker adjustment and leaning it out, the off idle responce is way better and seat of pants dyno I really picked up alot of power from 1500 rpm ALL the way to 6500 (it still pulls like hell but not knowing what I have yet, I dont want to push my luck going any higher).

Thanks for all your help so far
EMC<----------Hopeing someone out there can save me a few hours!)

Hah hah, I'll bet you're wondering why nobody has replied yet. You just had to ask a carb question, didn't you? ;) If you don't find an answer here, head over to corvetteforum.com. There's a lot of sharp carb guys over there. Sorry I can't help ya bud!

http://chevyhiperformance.com/howto/45638/
http://moparmusclemagazine.com/tipstricks/mopp_0504_tune/
http://holley.com/TechService/Instructions.asp
http://www.holley.com/data/Products/Technical/199R9934-3.pdf

http://chevyhiperformance.com/howto/45638/
http://moparmusclemagazine.com/tipstricks/mopp_0504_tune/
http://holley.com/TechService/Instructions.asp
http://www.holley.com/data/Products/Technical/199R9934-3.pdf


Thanks, great info. Not what I wanted to hear, but really good info....looks like I am going to smell like gas again today...:D

I don't know if the Demon base is like a Holley but if it is you can put the butterfly screws in from the top and then you don't have to pull the carb to adjust them any more. They are still a pain to get at but you can get to them from the top. I did it on my Holley 850 dp.

The other day I had an interesting "play time" with my Camaro. Just to note, I have had it about a month and I only know what I can see from the outside, about the moter. I Adjusted all the rockers (found out I have a solid cam!). I set them a .025 because I have no clue what cam I have....and I reset the idle mixtre and droped the primary float back down to the middle of the site glass and went to reset the idle speed. Well I have a Speed demon carb and got the idle mixture to what I think is about perfect, but when I went to set the idle speed I was just haveing a real hard time setting it and not loesing the mix. I got it to run at about 1000 rpm (idled before at 800). Then I decided to look on Spdded demons website and figured out I have an idol ease base....Its a 650 mechanical secondary. I belive that moveing the butterfly stop screws, I have lost the setting on the transfer slots, which may or may not be alowing the carb to get out of the idle circut. My question, Is ther any way to rest the butterflys with out pulling the carb, or do I have to? I will say that between the rocker adjustment and leaning it out, the off idle responce is way better and seat of pants dyno I really picked up alot of power from 1500 rpm ALL the way to 6500 (it still pulls like hell but not knowing what I have yet, I dont want to push my luck going any higher).

Thanks for all your help so far
EMC<----------Hopeing someone out there can save me a few hours!)


With any carburetor your best bet is to start out with the transfer slots set where you want them, and then make a notation of where you adjust your speed screws from there in or out. Also you may need to double check your initial timing. If its too low it can cause a similar situation.

I am at 10 degrees BTDC at idle....30 total at 2500 rpm....vacume advance Mallory Unilite electonic distributer....

Thanks.

If it idled OK at 800 before you starting tweaking, the first thing I'd do is go back thru everything you touched. I'd even recheck the valve adjustments. You are sure this is a solid cam, right? Where was the timing before you started?
On a leaned on motor, timing at idle can have a huge effect on all this. 10 degrees is not much, and looking at your total # makes me think the car was dailed in with more. Going to 16 degrees initial and vacaum on full manifold will pick up your idle speed considerably, and allow you to close that primary idle stop a bunch.
There is no way I'd pull the carb and start tweaking on something new at this point.

If it idled OK at 800 before you starting tweaking, the first thing I'd do is go back thru everything you touched. I'd even recheck the valve adjustments. You are sure this is a solid cam, right? Where was the timing before you started?
On a leaned on motor, timing at idle can have a huge effect on all this. 10 degrees is not much, and looking at your total # makes me think the car was dailed in with more. Going to 16 degrees initial and vacaum on full manifold will pick up your idle speed considerably, and allow you to close that primary idle stop a bunch.
There is no way I'd pull the carb and start tweaking on something new at this point.


At 800 it really did not idle very well at all. It stayed running but loaded up alot. and had a TERRIBLE bog. Bog is gone and plugs look much better...

So you think the next step is to reset the timeing then adjust the carb again? I now have a vacume gauge...I have yet to use it. We got a little snow and its been "kinda" cold since I picked it up....

If you have a decent size solid cam it's going to want more than 10 degrees at idle. Try upping it to 15 or 16. That should help you idle, throttle response a bunch.

If you have a decent size solid cam it's going to want more than 10 degrees at idle. Try upping it to 15 or 16. That should help you idle, throttle response a bunch.
Totally agree
My basic guidlines for initial advance is "if it pings at part throttle it's too much" and "if it won't crank hot, it's too much" and sometimes the first one can be worked out playing with the advance curve and power valve.
Use that vacaum guage. Duct tape it to your windshield and go for a drive, they are fun to watch.
Since my gen light still works, I'm seriously considering replacing my voltmeter with a permanent vac guage.... but afraid if I'm watching the console all the time I might run off the road!

I have it idleing at 950 rpm, with 9" vacume, any lower and it just loads up. I switched the vacume line from the distributer to the non ported and it seemed to help a little, I have to get a timeing light to adjust the timeing, but the vacume guage really helped me improve it for now....

Thanks all...