carb trouble

[rkmj67]

hello everybody, i have a demon 575 mech sec carb on my 327, front idle mixture screws have hardly any effect, idle speed screws are 1/2 turn in on primary and sec, car is very rich at idle, eye burning exhaust, any suggestions.

[wikd69]

hello everybody, i have a demon 575 mech sec carb on my 327, front idle mixture screws have hardly any effect, idle speed screws are 1/2 turn in on primary and sec, car is very rich at idle, eye burning exhaust, any suggestions.

A blown power valve will do that.

[rontoomanyprojects]

They are also sensitive to the blade position with the transfer slot. You want about .020" of transfer exposed when the throttle is closed. Unfortunately you will need to remove the carb to see this. If you have the idle ez, you can adjust the idle with that, and leave the idle screw alone. Power valve should be less than the idle vacuum. Otherwise it will open at idle and richen the circuit. Hope this helps. Hopefully some of the carb experts will chime in and give you some more advice.

[want-a-be]

rontoomanyprojects is dead on. While you have that carb off take it apart and look in every oriface...I'm betting you'll find some metal shavings in it. So Far every Demon carb I've had apart had it in it.

The EZ screw can screw you also. The ones I have been around have been seated all the way down. Messing with the idle screws.

Don

[wikd69]

rontoomanyprojects is dead on. While you have that carb off take it apart and look in every oriface...I'm betting you'll find some metal shavings in it. So Far every Demon carb I've had apart had it in it.

The EZ screw can screw you also. The ones I have been around have been seated all the way down. Messing with the idle screws.

Don

want-a-be, I found the same thing - I'd ordered two of BG's blower carbs, pulled the bowls and metering block to check jets, etc., and had a pile of aluminum shavings fall out on the bench. I wasn't impressed. I put them back together, put them back in the box and shipped them back. Then I bought these Holleys and they were perfect right out of the box.

One engine builder I know says he uses Barry Grants a lot but always blueprints them when he gets them. He says it's the only way he can be sure of the consistency of the product.