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-   -   Fuel stink ? (https://www.racingjunk.com/forums/showthread.php?t=18430)

chevguy65 09-21-2007 03:46 PM

Fuel stink ?
 
Ok,

With the help of Tom, Ed and Donn I got my carb fairly well dialed in.
It runs better than it ever did, but I did put on a new Demon 750 and removed the Holley.

Anyway, the thing is I cannot lean the carb anymore than it is without it running rough and stumbling, it is in the zone...hehehe...but it stinks enough to burn the eyes if you stand behind the car and it is turning my exhaust tips black from the carbon.


What do I need to do?
BTW. I am running an electric fuel pump and pressure is set to about 4 1/2 to 5 lbs.

bjuice 09-21-2007 06:38 PM

they way you describe the exhaust ..etc...there is NO question the carb is way tooo FAT ( RICH)...What size front and rear jets do you have ?

remember fuel pressure at the regulator will not determine the lean or richness of your carb..only your main jets...and if you have a power valve it could effect the rich side your smelling...

you also need to bring that fuel pressure up to a minimum of 6 to 6.5 lbs sitting there idling..remember you got it dead headed sitting there against the regulator..so it will drop a minimum of 1 lb or more under full throttle....anything under 4lbs is dangerous of burning an engine up...even the factory Hobb switches ( fuel saftey switch) is pre-set at 4lbs from the factory...this means when the fuel pressure hits the 4lb mark the hobb switch will kill the circuit its wired to stopping everything in its tracks...most hobb switches are wired into the NOS fuel side for extra saftey in killing the NOS in case the fuel pressure drops to a un-safe level ( 4 lbs )

Brian

topsportsman1 09-21-2007 06:54 PM

Also Carl,
You may need to tune the idle air bleeds,but that should be done with precision.Just don't let anyone do this,as .003-.007 bigger will make a differance on the idle richness

Also,turning the air screws in leans it,Out richens it,so try to get the air screws all set the same,between 1 turn and 2 turns,If that won't cure it,I'd say the idle air bleeds need tuning



*EDIT*

gdmii 09-21-2007 06:57 PM

Don't know anything about Demons but are they backwards? On a Holley turning the idle mixture screws in leans it. Just wondering.

George

topsportsman1 09-21-2007 07:19 PM


Originally Posted by gdmii
Don't know anything about Demons but are they backwards? On a Holley turning the idle mixture screws in leans it. Just wondering.

George

Yes you are correct George,I had it backwards,I wasn't thinking...as always

gdmii 09-21-2007 07:28 PM


Originally Posted by topsportsman1
I wasn't thinking...as always

Just a brain fart. :D I have them on a regular basis.

George

topsportsman1 09-21-2007 07:34 PM


Originally Posted by gdmii

Originally Posted by topsportsman1
I wasn't thinking...as always

Just a brain fart. :D I have them on a regular basis.

George

All apart of getting over the hill.I seen it hapening quite alot lately :P :P :P

chevguy65 09-22-2007 07:07 AM

Thanks for the replies.

Brian the jets are 73 front ant 84 rears.
I will set the pressure back up to 6lbs.

I have adjusted the 4 corner idle screws about as lean as I can.
Any leaner and it starts to stumble and die.

The funny thing is, the engine loves the new carb, I am seeing a major improvement in low end acceleration as well as more top end pull.

As far as the air bleeds I need to find a carb guy I can trust, and no one here in town fits that bill, at least I have not met them yet...lol

I will try these things and again appreciate all of your help, I am getting to where I am doing more and more work myself and this is definately something someone that knows there stuff needs to help me with.

Thanks again guys!!!!!!!!!! 8)

margaritaman 09-22-2007 08:34 PM

Carl, Have you adjusted the "idle-eze?"

http://www.competitionplus.com/04_15..._idle_eze.html

If I can get mine to idle with two Demons at 950 rpm using the idle-eze screw then so can you. Mixture at idle is ~ 13.2:1

bjuice 09-22-2007 09:50 PM


Originally Posted by margaritaman
Carl, Have you adjusted the "idle-eze?"

http://www.competitionplus.com/04_15..._idle_eze.html

If I can get mine to idle with two Demons at 950 rpm using the idle-eze screw then so can you. Mixture at idle is ~ 13.2:1

WOW !!..that show queen is THUMPING at 632 @ 111 mph...very impressive for a car that looks and drives like it does..my hats off to you !!!


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