Plugs still white...

[440Charger]

Ok guys - some of you may or may not remember my 440 pinging problems, but check this out:  I've been running lean and this spring we replaced the 5/16 lines with 3/8 lines, and replaced the stock pump with a Carter 120gph pump.  We've been running it for a month or so since, and I checked a plug the other day and it was white almost all around...pure white.  There was a light tan area in one spot but that's it. 

The carb is a speed demon 750, and it has been jetted up about 10 steps.  Any opinions on how I could still be running lean?

thx,

- Doug

[GoodysGotaCuda]

Got a big vaccuum leak? What about timing? 

[Chryco Psycho]

The demon is the problem , I have been through this with some demons in the past , try upjetting 5 more steps
 does it have changable air bleeds , you could install a smaller air bleed for the jet circuit , or insert a piece of wire into the existing air bleed if not interchangable , the jet bleeds a re closest to the center of the carb , the outer ones are for the idle circuit 

[440Charger]

If I need 15 jet steps over stock for this carb I'm going to put it on my lawn mower.  I wasn't around for this but my dad said that the 850 Demon we had was too rich....I'm thinking of throwing that back on.  My local carb shop told me to dump the demon and use an edlebrock 800 avs thunder series or a holley.  I'm thinking of switching carbs.  That would be #4 

No vacuum leaks that I know of.

Any thoughts on carb choice?

[IMNCARN82]

I think I'm about to go thunder series

[matt63]

Just out of curiosity....what cam do you have and how much intake vacuum do you have at idle and at cruise?

[Chryco Psycho]

If you Have to use an EDDY carb get the Thunder , it is somewhat adjustable at least
 my Choice would be a Holley though or Proform

[440Charger]

Just out of curiosity....what cam do you have and how much intake vacuum do you have at idle and at cruise?

Cam is a Lunati 480/230@.050, 109 LSA

Never tested vacuum.  I don't know how actually 

[Chryco Psycho]

put a Vacuum gauge on a small manifold vacumm port , see what vacumm you have at idle & at idle in gear , should have 12-14"

[matt63]

put a Vacuum gauge on a small manifold vacumm port , see what vacumm you have at idle & at idle in gear , should have 12-14"

That sounds about right because my cam is similiar at 228@0.050 with 111 Cl and it runs at 12"

[moper]

Yuo can bolt anything you want to it. It will need tuning in any case. Hence the 4 carbs...lol. CP is right. Demons IMO come with air bleeds at least 2 steps bigger than they should, and the result is you can go as big as you want on jets, and it means squat. Because the air is getting pulled in easier and faster than the liquid fuel thru the metering block. Make sure the float levels are right, and I think what you've demonstrated is your fuel delivery system (the old one) was fine. The carb(s) need tuning. so tune it.

[ShelbyDogg]

Weld in an O-2 bung into the exhaust, put in and O-2 sensor and hook up an air-fuel guage.  What looks white to you could just be  too hot of a plug.   Whatever carb brand or size jet you use, you still wont know if it is right. Even a junk yard sensor, a 14mm nut from the auto parts store, and a digital multimeter is all you need to be on your way to the 2000s.

[matt63]

Weld in an O-2 bung into the exhaust, put in and O-2 sensor and hook up an air-fuel guage.  What looks white to you could just be  too hot of a plug.   Whatever carb brand or size jet you use, you still wont know if it is right. Even a junk yard sensor, a 14mm nut from the auto parts store, and a digital multimeter is all you need to be on your way to the 2000s.

I just installed one of the Innovate LM1 wide band O2 sensor w/the portable 12v air/fuel ratio meter.  It takes alot of the guess work out.  All you have to do is guess at how much of a jet change you need.  You can throw $375 at this or $375 at a new carb which may not solve any or all of the problem.  My new Holley HP750 street had to have the jets dropped 4 sizes just to get it in the ballpark!

[440Charger]

Yuo can bolt anything you want to it. It will need tuning in any case. Hence the 4 carbs...lol. CP is right. Demons IMO come with air bleeds at least 2 steps bigger than they should, and the result is you can go as big as you want on jets, and it means squat. Because the air is getting pulled in easier and faster than the liquid fuel thru the metering block. Make sure the float levels are right, and I think what you've demonstrated is your fuel delivery system (the old one) was fine. The carb(s) need tuning. so tune it.

Well I actually have been trying to tune it.  Once the jetting wasn't working I upgraded the fuel system which did make a difference.  I called a local carb shop and asked about replacing the air bleeds and he said it was as much $$ as buying a new carb.  The float levels are set correctly.  If I knew how to change air bleeds myself I would, trust me.  I'll check the manual and see if I can figure it out. 

I like the idea of an AF sensor, I'll check those out - thanks.

[Chryco Psycho]

try inserting a small diameter piece of wire in to the air bleed , this will act as if you have a smaller bleed in place