Hot Rod Forum banner
1 - 20 of 24 Posts

·
Registered
Joined
·
164 Posts
Discussion Starter · #1 ·
I just got my 575 Speed Demon carb. Well the thing was way too rich at idle no matter what the adjustment was on the float and mixture screws. So I pulled the primary bowl off to check thing's out. I foung brass shavings/chips, and a cut o'ring on the needle and seat. If you get a new carb, do yourself a favor and pull the bowl's off before installation and give it a good look over!!:thumbup:
 

·
Registered
Joined
·
297 Posts
That is a real bummer!!

I have seen others claim that they switched to Barry Grant carbs because Holley's would put out carbs like this. Good thing none of that stuff made it to your engine. You will have to blow out the plates real good. Hopefully you get it all out. Good luck.
 

·
Registered
Joined
·
164 Posts
Discussion Starter · #4 ·
Yep, I couldn't believe it. I'm gonna call'em on Monday and let 'em know. I expected a lot more from the carb than that. I had to go to the local speed shop and get a replacement needle/seat and o'ring. When I told them why I was having to do this they didn't seem surprised. I wished I had asked them if they had heard about this before.

I must say that the carb has really brought my engine to life. I need to do some fine tuning. When I get on it, there's a slight hesitation off idle and I think the secondarys come in a little too soon. All and all I am happy with the carb so far. Time will tell...
 

·
Registered
Joined
·
4,104 Posts
sounds like:

the "bean counters" are taking over or Barry Gant needs to spend less on advertising more on Q/C!
"Build it (right!) and they will come"....from the movie Field of Dreams?

told ya it would make a big difference, even messed up with less cfm

guess our vacuum test is delayed a little
 

·
Registered
Joined
·
164 Posts
Discussion Starter · #6 ·
Ya know what's funny. I gave up on the vacuum advance. I disconnected it completely. Until I can get an adjustable one that I can lock out forget it.. Mine swings way too far. Ported or manifold it's not happening.. I think Moroso make's one, anyone know for sure who make's a good one. :confused:

(told ya it would make a big difference, even messed up with less cfm)

Hey Red65, less CFM? I'm confused, this 575 was actually bigger than I wanted. I expected the 525 Road Demon to be the good choice. By the way I couldn't agree more, Bean Counters screw everything up.

One weird thing about the carb is that it came with it's little test card signed by a tech. It said it was all good, well how could that have been with the o'ring cut on the primary needle/seat. All it would do is flood.. Can you say pencil whipping.. :D
 

·
Registered
Joined
·
4,104 Posts
underdog,

It is ALOT less cfm compared to what you had, no more dripping gas at "0" Hg

Never tuned a Demon but (if you keep it) I think it's ok at 575.

I have less cam and smaller valves and 600cfm and I can keep 2-3Hg at WOT launch

(somewhere on the net there is a Holley and Edelbrock marketing guy saying "write more underdog! write more!)
 

·
Registered
Joined
·
164 Posts
Discussion Starter · #8 ·
Yea no doubt! I think i'll stop here giving Demon a hard time. I think it's a great carb, I would honestly buy another without a doubt. It's not unlike me to get the curve buster. It may have been the one in a million carb, just glad I found the problems. I do know that I will no longer use Q-jets, probably a great carb, just not my flavor..:D
 

·
Registered
Joined
·
297 Posts
underdog305 said:
Ya know what's funny. I gave up on the vacuum advance. I disconnected it completely. Until I can get an adjustable one that I can lock out forget it..
You really need to rethink about using the vacuum advance. Crane, Accel, MSD, etc., all have the same adjustable vacuum advance. It will make your engine run more efficient, make plugs last longer, etc.

HERE ss Jeg's section for them. I am sure Summit has them too, just not as user friendly to give the link.


If you have not fully tuned your carb, HERE is the manual for your carb. I would make sure and go through it thoroghly.
 

·
Hotrodders.com Moderator
Joined
·
2,783 Posts
carb

Your name will go on a long list for this problem so don't feel to bad. If you do a search on this site you will find threads concerning the bg problems...

Keith
 

·
Registered
Joined
·
164 Posts
Discussion Starter · #11 ·
Yea, that's what i've heard about the plugs. I have struggled with that stupid vacuum advance, I just cant get it right. I'm gonna get an adjustable one soon.

Thanks for the links, much appreciated!!!

As far a being included in the long list, YEP!! It's one subject that keeps on going and going and going...

It got the best of me. Fine tuning the Demon is truely fine tuning. A little can go a long way with Mixture screws. I'm kinda confused on the Ez-Idle that is used to adjust Idle. You set your butterflys then you set your mixture. Ok, then your supposed to adjust your Idle with the screw at the bottom of your Base Plate. (this is thru the air cleaner stud hole). Mine doesn't do squat. Nothing happens when I turn it. I received the carb and it was all the way clockwise, basically closed. I turned it 1 and 1/2 turns CCW like the book says and nothing changed. I dont get it..
 

·
Registered
Joined
·
297 Posts
I am sure if you had an adjustable vacuum advance, you would get it right on. Just like many others have. But until you get one, you need to keep it disconnected in order to keep the detonation out of the picture. It is further down the "tuning path".

As for your carb, from what I understand, the idle eze is used to be able to close the butterflies more and get proper idle circuit metering. Why it does not do anything, ??? You may have uncovered another problem. It should raise the idle by opening it. I bet your carb is covered under warranty, from finding the crud you did, and then having to buy new parts, and now this. BG should stand by their warranty. Good luck.
 

·
Technical Support Barry Grant
Joined
·
1,500 Posts
Carburetor Problems

underdog305,

We apologize for the problems you've had with the carburetor. Depending upon how the o'ring was cut it may have passed the flow testing. The only time the Idle-Eze will be used is if your cam is large, and you need to open the butterflies too far exposing the transfer slots. If you're still having problems, please contact our technical department directly at (706) 864-8544.
 

·
Registered
Joined
·
164 Posts
Discussion Starter · #14 ·
Hey Tech @ BG, my Cam is a 218' @.050 w/.454 lift. Is this considered a big cam? Would this enable the Idle-eze adjustment? My reason for asking is.... if so, there's something wrong with the carb. The o'ring was cut in half. One half was in the fuel inlet gallery and the other half was on the needle/seat assy. I'm becoming a little concerned with the carb because I do what the paperwork/dvd say's, but I still have an off idle stumble. It backfired thru the carb (more like a burp) today and actually stalled. The timing is correct, everything mechanically is correct. Ignition and fuel delivery problems can imitate each other, but in this occasion it's the carb set-up or???? What do I do??:confused: :D
 

·
Registered
Joined
·
297 Posts
Underdog,

As [email protected] said, "The only time the Idle-Eze will be used is if your cam is large, and you need to open the butterflies too far exposing the transfer slots." In other words, if you have to have the butterflies open too far to have the engine idle, it will expose the transfer slots too much, resulting in improper metering of the idle circuit. This is where the Idle-Eze comes in, and it is supposed to allow air in, so that you can close the butterflies back to properly set them to get proper metering of the idle circuit. On a Holley, you would have to drill holes in the butterflies, due to not having this "feature".

Your cam does not seem that radical, regardless if it is going in a 305.
 

·
Technical Support Barry Grant
Joined
·
1,500 Posts
underdog305,

Your cam is actually on the mild side for the way that carburetor is calibrated. Is the backfire under a hard acceleration or light acceleration? Has anything you've done made the problem better or worse?
 

·
Registered
Joined
·
164 Posts
Discussion Starter · #17 ·
The backfire (out the carb) was just off idle. The only thing I can do now is close the idle-eze adjustment screw (it's @ approx 1 turn open now) and start fine tuning again. It seems better when the idle mixture screws are toward the rich side, you can smell it out the exhaust. I'm thinking about taking the carb off and verifying that the secondary plates are NOT revealing any of the slot. Once it's transitioned past idle it seems great. It pulls strong.
 

·
wind & fire = guides to power
Joined
·
1,529 Posts
Popping at idle and runs good otherwise?

Sounds like case of slow timing to me. What's your initial advance? your total?

Have you checked that the cam to accel pump linkage is tight and the squirters begin squirting as soon as the throttle is moved?

If those check out what accelerator cam(same as holley guys?) and squirters do you have?
 

·
Hotrodders.com Moderator
Joined
·
2,783 Posts
carb

What kind of initial timing and total timing are you running???

From what i am seeeing in your post it sounds like you may be a little late with the timing...

Keith
 

·
Technical Support Barry Grant
Joined
·
1,500 Posts
Popping back through carb

Underdog305,

If you’re not running enough initial timing it can cause the engine to run rich at idle. This will cause you to go in leaner than necessary on your mixture screws. First double-check your initial timing. It should probably be around 15 degrees on a combination like yours. From there make sure the secondary butterflies are completely shut. If the problem still persists at that point try raising your primary float level up a little in the front window.
 
1 - 20 of 24 Posts
This is an older thread, you may not receive a response, and could be reviving an old thread. Please consider creating a new thread.
Top