Thread: carb adjustment...
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10-21-2006 05:14 PM #1
carb adjustment...
1973 chevy el camino 350. 650(?) Quadrajunk.
My valves are toast... like so badly that i actually get puddled gasoline out of the exhuast.
I've got two main questions here.
1.I'm having trouble getting the carb adjusted (wont start unless I keep my foot on the throttle at about 1200rpm.)
It ran just fine two days ago until I tinkered with the carb to lean out the mixture some... but now I cant get it to start at all
2. I have a set of heads with only like 4,000 miles on them, valves are in great shape and i have a new set of lifters and pushrods... would it be worth my 50 dollars to put the newer heads/lifters/pushrods on and old engine with very low compression.
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10-21-2006 05:47 PM #2
OK ill start over on the adjustments, there are only two right?
If it's not gas then what is it? It is quiet a bit of moisture.
Should I still put my newer heads on or is that a waste of time?
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10-23-2006 12:56 AM #3
OKie so I got her running and it runs very smooth.
I seated and backed both screws out two turns, it fired right up but it idled at 3000rpms... lol. So then I backed the idle screw out about 4 more turns and the air/fuel screw out about a half turn. The idle is still a little high (1100ish) but it runs really smooth and clean.
Should I back the idle screw out more? or is the higher idle due to my air/fuel mixture still being wrong?
My assumption is that the carb is leaner, because the engine is running hotter now then it did before (but thats only an assumption, both oil and coolant are full)
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10-23-2006 06:17 AM #4
If the valves are "toast" as you say, you're wasting your time trying to get a smooth idle. The carb can't handle a fluctuating vacuum signal like that.
The heads will fix the idle, and run smoother, but if the rest of the engine is worn badly, it could turn into a smoker.
I wouldn't waste the new lifters on an old cam. If the engine is that bad, it needs overhauling. If you are really low on cash and need a beater badly, the heads might be worth a try, but don't sink a lot of dough into it.
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10-23-2006 01:21 PM #5
Ya actually I noticed when I was turning the idle out the choke kinda popped into the open position... so that means I should turn her in a bit correct?
Well my dad told me the moisture from my exhuast ment the heads were bad (but hes becoming rather senial in his days so sometimes its hard to tell if hes right or not, without asking someone else first.)
But the engine already is a smoker... i burn a quart of 50weight a week... and I cant take it past 2500 rpms without burning oil.
I just need a couple months life out of this engine while i work around my other stuff.
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10-23-2006 02:59 PM #6
If you are burning oil, your rings are toast, not your valves....although, they could also be bad.
An engine puts out a lot of moisture whether it is good or bad. Most of it evaporates in the exhaust system.
What screw are you turning to adjust mixture.............sounds to me like you are turning the idle screw or the choke adjustment screw.
Also, sounds to me like you should study up on how an engine works...............
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10-23-2006 03:51 PM #7
Well I knew the rings were toast, but my dad told me the moisture in the exhuast was from bad valves.
It's hard for me to know whats going on because my dad is going cenile, and my friend (whom is going to automotive school) gets a really big head about things and whenever I contradict him he gets butt-hurt like a little girl.
Atleast I'm learning and willing to admit my mistakes
Well I gotta wait for the truck to cool down I had to run errands today, and since its best to adjust a carb stone cold (correct?) I'll tinker with it tonight.
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10-23-2006 03:59 PM #8
Ok well.. when i started it this morning it idled at 750rpms (fairly smooth) after it warmed up it went to 1100rpms... Choke needs adjusted still correct?
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10-23-2006 04:01 PM #9
Sounds like your choke isn't kicking off of fast idle.....Lubricate the carb linkages, that may help.
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10-23-2006 04:03 PM #10
Ya it doesn't kick down at all... It used to before I messed it up lol. But now it doesn't. I'll use some WD40 and see if it will kick down after that..
Thanks guys your awesome I'll let you know if I pass emmisions or not.. it's that time again for me.
Welcome to CHR. I think that you need to hook up your vacuum advance. At part throttle when cruising you have less air and fuel in each cylinder, and the air-fuel mixture is not as densely packed...
MSD 8360 distributor vacuum advance