New to all this, fighting my new carb on my c10
 

Well I'm a brand new member, but I have read a lot of posts from here in my quest to understand what my problem might be. I am looking for advice on what to do next.

First off I just got a 1970 c10. The engine in it is not original, the guy I got it from said it was swapped out. I don't know when it was done. The casting number says it's from a 1971 caprice with a 2 barrel carb. But it had a 4 barrel quadajet on it. And the casting numbers on the heads say thy are from a 305. So I got a bastard engine.

When I got it I replaced everything as the carb was not working right. I got a brand new eddlebrok 1406 4 barrel. and all new ignition. It runs good but has so lag from idle. But my big question is this. I'm at about 5,000 ft elevation and I'm wondering if the carb is running to rich. The exhaust is VERY stinky and burns my eyes. If I walk past the tail pipe while it's running I will stink all day. Also I ran a compression test and I'm at 120psi and according to my math with a compression ratio of around 9:1 and at 5000 ft elevation I'm in the ball park being that my atmosphere pressure is only around 12.3 psi up here. I'm about 16-17" of vac. But what got me concerned was when I put some gas in it and did the math and was only getting 7mpg. I know I should not get great MPG but 7 seams a bit low. I do have what looks like a little carbon on the plugs. But I don't drive it a bunch. About 3-4 miles a day.

I picked up a eddlebrock carb tuning kit as there manual says I need to be about 8% lean at my elevation. But I'm clueless as I kinda got a bastard engine. But I did pass emissions at something like 135-150 hydrocarbons and our limit here in Utah is like 500 I think. My carbon monoxide was around 3% and out limit is 5% I think.

So any help would be very helpful. Thank you so much guys - JT

Re: New to all this, fighting my new carb on my c10
 

Oh and I also installed a pressure regulator between the fuel pump and carb. Right now I have it set to 5.5psi.

Re: New to all this, fighting my new carb on my c10
 

Sounds like you're running rich at idle and you might be OK on the primary and secondary circuits. Before fooling with anything else set the idle air circuit using the idle mixture screw to get the idle circuit mixture to lean out some. That carb uses both jets and metering rods to set the fuel -air ratio in both main and secondary circuits. you will want the manual to set those up properly but if you passed emissions I am guessing that your main and secondary Air fuel ratio is already close as that is usually measured well above idle. Go here for the manual on that carb: http://www.edelbrock.com/automotive/...404_manual.pdf

Re: New to all this, fighting my new carb on my c10
 

Don't even touch that carb till you optimize your timing!!
At your elevation you can run way more than stock timing.
Do you know what your initial timing is set at?
The rich smell is due to your idle speed. You're likely idling on the power circuit.
That can be fixed by optimizing your timing!!

Re: New to all this, fighting my new carb on my c10
 

geezer hit the nail on the head. More timing is the key.

Re: New to all this, fighting my new carb on my c10
 

I have been playing with the timing a bit as stock timing did not seam right. Book says like 4deg advanced. Right now I think I'm at 12 deg advanced I can go more but I don't know where to stop. I can get to a point where the engine changes sound and seams to be having a harder time but that's WAY advanced. I have the vac advance connected to the ported side on the carb. I have tried manifold vac advance and it idles fine at what I'm guessing is somewhere around 20-30 deg advanced. I am now switched back over to ported vac. When using manifold advance I have to turn the idle screw way down as it will jump from 700-800 rpm on ported to way over 1k when I switch to mana vac.

Re: New to all this, fighting my new carb on my c10
 

I have set the idle mixture screws using a vac gage. Backed them out till I got max vac.

Re: New to all this, fighting my new carb on my c10
 

Try 16 initial. Hook your vac advance to manifold. Turn your idle way down so it keeps running and then adjust your mixture screws.
See what rpm it will idle at. If it won't idle at 700 rpm then try it on ported.
You might need to limit the mechanical and vac advance in the distributor.
As a reference I ran a sbc at 3500 feet elevation. Ran 22 initial, 12 in mechanical and 10 from vac advance.

Re: New to all this, fighting my new carb on my c10
 

So set timing to 18deg advanced with vac advanced not connected. Then connect the vac advance and adjust rpm to around 700 and re adjust fuel mixture screws.

Re: New to all this, fighting my new carb on my c10
 

Yup.
After you set it to 16 or 18 initial see how it starts. If it cranks hard pull the timing back 2 degrees. You want to find the optimum initial. I'd try 16 first. If it starts easy try 18.
See how it idles then hook the vac hose on manifold port and turn idle back down. If it idles too fast then try it on the ported port.
Adjust your mixture then test drive.
If it starts nice at 16 or 18, idles at 700 and doesn't ping when you drive it you should be good.
If it pings you might need to reduce your vac advance amount.

Re: New to all this, fighting my new carb on my c10
 

If you passed a smog test there's no way you're running rich. Or running on your power circuit at idle.

Re: New to all this, fighting my new carb on my c10
 

I have been fighting with my Eddy for 2 years. Yesterday I called them, spent 5 minutes on the phone (after about 15 on hold) with a tech, gave him the engine specs and he told me exactly which metering rods and springs to run and where to set timing.

I'd recommend calling them. Also ordering the tuning kit so you'll have the rods and springs.

Re: New to all this, fighting my new carb on my c10
 

Hey just a heads up.. here in utah if your vehicle is over 40 years old you are eligible for a vintage car license... you can register for $10 without emissions or safety

Re: New to all this, fighting my new carb on my c10
 

I have the tuning kit but have not opened it yet because if I open it I can't return it.

Re: New to all this, fighting my new carb on my c10
 

Call them and find out what jet and spring you need, then open it.

Most likely you will end up opening it.