ldollar

Just kidding about taste.
I am trying to make some adjustments to my Barry Grant Speed Demon carb and am afraid of running too lean for fear of damaging the engine. BUT here is the problem....this rookie doesnt really know how to tell if it is lean or rich.

From what I understand:
Rich: More fuel, less air. Stronger gasoline odor, lower idle speed (is that wrong?)
Lean: Less fuel, more air.

I have read to "check the plugs" for grey (lean) or black (rich) but I dont even know what the plugs are(!!!) JMD sent me an awesome DVD and manual but I couldnt find anything about the "plugs" in there. I know this stuff has to be pretty basic. I am thinking that I will probably take it to the builders who did my 347 and have them tune it all up good for me but in the meantime I want to make sure I am running more rich than lean. How do I make sure of this?

Thanks, guys!

connor90

by plugs they mean spark plugs.

sarNz

well on my bike if you pin the throttle and the engine bogs then theres too much gas. I would imagine more gas also needs a higher idle since otherwise youll just stall out. Can you adjust the carb while the car is running? On my bike (old school 85 honda baby, actually runs off of 2 carbs lol) it's no problem adjusting the idle.

ldollar

wow, spark plugs. im a f@ckin genius. Thanks Connor.
Do you know if you can just pull them and look, without f@cking up the timing or something?

hmmm...not sure about this one.

Yeah I have been making the adjustments while the car is running, warmed up to around 180-190. I was trying to make adjustments with the shifter in Drive with the EBrake on since I got an auto (C4) and if I tuned her while she is in Park, the idle is too high and as soon as I shift into Drive she wants to cut out on me. I remember those old school Hondas. I almost died on one when i was a kid. damn that was one of my nine.

Today when I was trying to make adjustments, I got it pretty good, but I think it is just not perfect. When I parked her after cruising around for awhile and shut her down, the engine made a weird noise when it stopped... hard to describe but it just sounded like everything just stopped faster than it would like to. Not really a scary sound but usually when I shut her off, she just goes quiet and its all good. No extra noises or whatever.

I know this is too much info but hey, you never know. Maybe you have been through this exact thing before and it will ring a bell! Thanks guys.

67mustang302

Black too rich, white too lean. You want a greyish-tan color on the porcelein. If it bogs on acceleration it could be too rich or too lean, if it sputters downtrack it's too rich, backfiring when you crack the throttle isn't enough accelerator pump shot, surging is too lean, detonation is WAY too lean....or too much ignition timing, if it stalls on braking or cornering your float level is wrong, fuel pressure is too high, or your idle is too rich. You want to back the idle screws out until the engine runs smooth, then back them out just a bit more, like 1/4 turn. Make sure your ignition timing is correct, or all the carb tuning is for naught

ldollar

So I can just pull the plugs out and check them and put em back? It wont F anything up?
I wouldnt describe it as bogging on acceleration but it just isnt as jumpy on the gas as it was when i got it.
No sputtering, she still has plenty of go.
No backfiring at all.
Could you elaborate on "Surging" a little... what do you mean by that?
And how would I know what "Detonation" is...even though nothing I have experienced could be described as that, I hope!
Not stalling on braking, or cornering.
I have adjusted it so at idle (remember this is an auto), it is at about 1100rpm... is that okay???
I think my timing is all good. I have no reason to think otherwise.

Thanks for all the thoughts here, 67mustang302

67mustang302

Set the idle for in gear. And yeah, pull the plugs and you can put them back, but if they're sooty or dirty you won't get a good read if you recheck the same plugs, so you may want to buy a few extra plugs just for tuning purposes. Detonation=bad and you'll hear a sound similar to marbles or rocks rattling around in a can. And surging is when you're driving the car will surge....it accelerates, then slows down, then accelerates, sometimes it's rapid enough that it seems like it's a sputter. Read your carb manual and learn how it works, and read up on drivability symptoms. Knowing how to tune a carb is mostly knowing about how an engine and carburetor work

bluovalguy

Buy a vacuum guage ($15-20) and try this:

http://www.fordmuscle.com/archives/2...ockCarburetor/

It is for an edelbrock, but the priciples are the same.

Decurion

It take somewhat of a 'tuned ear', but you can setidle mixture just by listening to the engine. Pay attention, and you can hear it speed up slightly or slow down as you turn the mixture screws. It will run the smoothest and fastest when the mixture is right. Also dont forget to keep each mixture screw about the same number of turns out. IE, dont have one screw 5 turns out, and the other 1/2 turn out. It doesnt have to be exact, but keep em close. To help tune your ear, use a vacuum gage to achieve the highest reading. I would also set idle speed down to about 850. Assuming the engine isstock orclose to it, it should have no trouble staying running in gear.If you know how to check your timing, it should be around 10-12* with the vacuum advance (the silver can on the distributor with a vacuum hose connected to it) disconnected.Timing will affect your idle speed and quality as well. If the car ran good when you got it, chances are that timing is ok where it is, but probly not a bad idea to at least check.

JMD

+1 on all of this....