tuning a demon carb

[project67]

anyone have experience tuning a demon carb? im having a problem with the idle circuit being too rich. off idle is ok. please help

 

[Shakin66]

Do you have the book that came with the carb? If not I could fax you what I have if that helps?

 

[FORCED2DV8]

What series Demon do you have? what cfm does it flow?? and what size engine c.i. is it?? Did you adjust the idle mixture screws? And do you run elctric fuel pump or mechanical, whats the fuel pressure set at??

 

[66HertzClone]

I found mine running rich at idle to, I adjusted the float level to the lowest setting on the windows of the bowls, it was much better after that.

 

[DrStang]

Ditto, on the float setting. Demons are known to idle rich.

 

[project67]

thanks for the replys. my carb is a road demon. 625 cfm vac. secondaries.
the engine is 5.0 with gt40 alum heads and x303 cam. i have the floats at the center of the sights and the idle set screws 1 turn from being all the way in. can this be a timing problem? i didnt think the float levels had anything to do with idle circuit, but again, im not really a carb guy. i pulled the carb off last nihgt and found there are slots in the bore that are supposed to look like squares when the butterflies are all the way closed. mine were not. i adjusted the secondary set screw to accomplish this and i will be reinstalling it and retesting tonight. my dad thinks the jets are too big-the were not numbered. arent theysupposed to be numbered? anyway, thanks for the input.

 

[project67]

by the way, the fuel pump is holley red, preset at 7 psi.

 

[foghorn67]

thanks for the replys. my carb is a road demon. 625 cfm vac. secondaries.
the engine is 5.0 with gt40 alum heads and x303 cam. i have the floats at the center of the sights and the idle set screws 1 turn from being all the way in. can this be a timing problem? i didnt think the float levels had anything to do with idle circuit, but again, im not really a carb guy. i pulled the carb off last nihgt and found there are slots in the bore that are supposed to look like squares when the butterflies are all the way closed. mine were not. i adjusted the secondary set screw to accomplish this and i will be reinstalling it and retesting tonight. my dad thinks the jets are too big-the were not numbered. arent theysupposed to be numbered? anyway, thanks for the input.

float levels. My demon was rich at idle too.

 

[10secgoal]

Halfway is way too high. The jets have nothing to do with idle. Screw them all the way in the, and try to kill the motor. If they go all the way in and it doesn't die, then you have a larger problem than an adjustment.

 

[project67]

if i turn the idle set screws in anything past 1 turn the idle starts to drop.
i will lower the float levels to the lowest mark and see what happens. i was also concerned about the carb being unable to support my cam. advertised duration at .050 lobe lift is 224 deg. i found out later the demon supports up to 220 deg. is this a big deal? when i bought the carb, the summit guy said it should work. do i need to step up to a speed demon?

 

[10secgoal]

No big deal. It'll work.HAHA, I wonder how they figure they can figure what a carb can support by duration @ .05

 

[69Rcode_Mach1]

Halfway is way too high. The jets have nothing to do with idle. Screw them all the way in the, and try to kill the motor. If they go all the way in and it doesn't die, then you have a larger problem than an adjustment.

The sight glasses on the demons are different than holleys they are supposed to be midway instead of just at the very bottom. So midway is where you want it. I agree on the jet issue, and also try to kill it see what happens.