Edelbrock 1405 carb running rich

[iamtherealJayy]

The truck idles all day once it’s ran a minute. I smell like gasoline right now just from being around the truck. It reaked sitting there smelling it running. But it chokes itself of something if you quickly press the throttle to wide open, if you hold it you can hear it basically quick running hit just do a few pops like it’s only running on a couple cylinder maybe? It held steady vacuum just idling the whole time. It never moved unless I hit the throttle then vacuum went down and bounced up before settling around 16 inches of Mercury.

 

[SirRobyn0]

Ok, so if it idles ok and is not smelling like gas then, then the mixture screws are not to blame, as they are the idle mixture screws.

I'm going to reiterate the need to be able to properly set the ignition timing, though I won't beat that horse anymore after this post. You don't seem interested in fixing that and it will just cause you problems by not addressing it. I know once you get it running better, you can set the timing close enough to run decently, but you'd be surprised how far off you can get it by ear, and if you could set it now, initial setting, and check vac and total timing with a light you'd at least know that was dialed in.

Sounds to me like this is an internal carb problem. You can pull the metering rods out of the carb and make sure the springs are good and the rods aren't hanging up. Check to make sure the secondaries area closed against the minimum air screw, for the secondaries, (this is not the idle speed screw.) If you need info on what I'm talking about let me know. But beyond that it's taking the carb apart. Given that it is not doing this at idle if you don't find a problem with the external stuff, I'd suspect that something inside the carb is not factory, as in maybe it's got much bigger jets in it, or different metering rods.

The hard thing about this is none of us can be there with you, and you do not know how this engine ran previously when it was last running. If you have another carb, or ability to borrow and swap a known good carb from someone running a similar sized engine that doesn't have a cam in it. If it runs ok with that carb, then you'd know it's in the carb for sure.

 

[iamtherealJayy]

Do you know how to make a sort of home made way or some sort of way to get #1 at exactly tdc or as close as possible? If I can get it to top dead center and make a mark on harmonic balancer and timing cover I’ll just use an adjustable timing light to get to 8-10° initial, I’m not 100% sure how to measure total timing. I’m pretty sure it’s supposed to be timing around 3000 rpm? As for the carb this is my first edelbrock, I know little too nothing about them, I’ve rebuild a couple quadrajets but that was all I ever did to them. I don’t remember why I was eager to get the edelbrock over the quadrajet I had rebuilt(just gaskets, needle and seat, accelerator pump, etc. no shafts or anything of that sort). I guess I knew I didn’t have enough knowledge to tune a quadrajet to run good enough at the time.

 

[SirRobyn0]

Do you know how to make a sort of home made way or some sort of way to get #1 at exactly tdc or as close as possible? If I can get it to top dead center and make a mark on harmonic balancer and timing cover I’ll just use an adjustable timing light to get to 8-10° initial, I’m not 100% sure how to measure total timing. I’m pretty sure it’s supposed to be timing around 3000 rpm? As for the carb this is my first edelbrock, I know little too nothing about them, I’ve rebuild a couple quadrajets but that was all I ever did to them. I don’t remember why I was eager to get the edelbrock over the quadrajet I had rebuilt(just gaskets, needle and seat, accelerator pump, etc. no shafts or anything of that sort). I guess I knew I didn’t have enough knowledge to tune a quadrajet to run good enough at the time.

On the carb question. If you have successfully rebuilt a Q-jet the edlebrock will be a walk in the park. Follow the direction in the kit, write down the number off the jets, the size of the metering rods and the color of the springs so you can look up what's inside and find out for sure if it's been changed up from stock. Seriously Edlebrock is an easy rebuild.

Total timing is measured where timing stops increasing, typically around 3K but sometimes a little lower. Basically your looking for the max advance you can get and on a stock 350 I'd expect it to be around 30 - 35 degrees some will say it can be higher, but that is a safe number and if you set to 10 initial and achieve 30 - 35 total, your getting 20 - 25 degrees of advance and that's what a stock HEI distributor should give you. Of course be careful when revving the heck out of it while your under the hood. I've done it many times but still find it a bit unnerving.

The best you can do to find TDC is to remove the #1 plug put your thumb over the hole and turn the engine over manually until you feel compression with your thumb. Then remove your thumb and put a long screw driver in there when you get to TDC it'll stop going up and then start going down. Do your best to find the middle of, where it's not going up anymore and it's starting to go down. Then make you mark. Remember some 350's have timing tab that's up high and obvious while others have them lower on the block nearly obscured by the PS pump. If you haven't looked by the P/S pump for a timing tab it might be worth checking for.

 

[iamtherealJayy]

I’ll look into a rebuild kit, I just didn’t want to mess up a $300 carb(what I think he said he paid for his new one), I have several old old holleys and quadrajet carbs laying around so I rebuilt the one on the truck but it was rough, oreillys gasket set for it wasn’t the right one so I ended up getting another gasket set and rebuilding a different q-jet. The metering rods are the thin “spikes” right? Kinda get smaller as it nears the tip like a step bit for a drill? I’m not sure about jets, will it be obvious what they are? I’ll yank #1 spark plug out ASAP and make a mark at tdc and time it to 8-10°, there is no tab that I can find I tried to do a full 360 around the harmonic balancer with my hand and I couldn’t find anything. Sprayed majority of a can of brake clean on the balancer trying to find any kind of mark. If it has a tab it’s the one I’ve seen pictures of where it’s at the 12’ o clock position and the water pump completely blocks it.

 

[SirRobyn0]

I’ll look into a rebuild kit, I just didn’t want to mess up a $300 carb(what I think he said he paid for his new one), I have several old old holleys and quadrajet carbs laying around so I rebuilt the one on the truck but it was rough, oreillys gasket set for it wasn’t the right one so I ended up getting another gasket set and rebuilding a different q-jet. The metering rods are the thin “spikes” right? Kinda get smaller as it nears the tip like a step bit for a drill? I’m not sure about jets, will it be obvious what they are? I’ll yank #1 spark plug out ASAP and make a mark at tdc and time it to 8-10°, there is no tab that I can find I tried to do a full 360 around the harmonic balancer with my hand and I couldn’t find anything. Sprayed majority of a can of brake clean on the balancer trying to find any kind of mark. If it has a tab it’s the one I’ve seen pictures of where it’s at the 12’ o clock position and the water pump completely blocks it.

Well I can understand not wanting to mess up the carb. I don't really have another direction to send you in though. Based on our conversation here I just can't image what else it could be. Yes the metering rods are the "thin spikes". Whatever you do when you go to put them back in the carb if they don't wanna go in just gently work them up and down until they do. Don't force them you can damage the tips.

You should read this: https://www.motortrend.com/how-to/rebuilding-tuning-edelbrock-carburetor/

It even says what the factory jets are for that carb so you can compare yours to that. It gives a really good info on how the carb works and a little about rebuilding it. They go into custom tuning a little bit, but you don't need to worry to much about that. If the jets and metering rods are the stock units it'll run a stock 350 just fine.

 

[Bextreme04]

Main suspect for an edelbrock carb on an otherwise stock 350 is too much fuel pressure and/or leaky floats. Stock 350 mechanical fuel pump will be cranking between 7-9PSI at the carb. Edelbrock floats tend to leak and not seal above 6psi, which causes it to run pig rich all the time.

If you turn the idle mix screws in all the way, does the engine die? If it keeps running just fine with the idle mix screws in all the way and the engine at idle, you are leaking fuel somewhere other than the idle circuit.

 

[iamtherealJayy]

@Bextreme04 Turning the screws in stalled the engine twice yesterday, vacuum would start bouncing around 10-12 and lower and then stall. I would loosen a quarter turn and start the engine, would have to give a little throttle input for a second or it would stall back out. It is currently snowing in Tennessee somehow so I can’t do much today, but I’m going to start by going to tdc and get the timing set right. The carb should be easy part after the timing is right.

 

[Bextreme04]

@Bextreme04 Turning the screws in stalled the engine twice yesterday, vacuum would start bouncing around 10-12 and lower and then stall. I would loosen a quarter turn and start the engine, would have to give a little throttle input for a second or it would stall back out. It is currently snowing in Tennessee somehow so I can’t do much today, but I’m going to start by going to tdc and get the timing set right. The carb should be easy part after the timing is right.

That's actually really good news. Best guess then would be your buddy had a pretty hot engine in his car then and the jets are WAY too big for your little truck motor. Good news is that the edelbrocks are stupid cheap and easy to dial in. I would get that timing straightened out and then buy an edelbrock calibration kit.
https://www.competitionproducts.com...s-Carb-1405/productinfo/EDE1479/#.YdclVWjMKUk
It will come with a range of springs, rods, and jets as well as instructions to dial it in. They give you a sheet that will tell you what to go too from what you currently have and some basic instructions. Since you have black smoke and your exhaust looks like that I'd say you are richer than 10:1 most of the time.
You can also try just ordering the parts you think you will need after reading this guide and looking at what you currently have installed compared to stock. If its a stock 1405(rod and jet) you can probably just switch to the smaller jet and larger rod in order to go two stages leaner. You would go from the stock #1 calibration to the #24 calibration by just ordering the jet and rod you need. Those would be the #1427 jet and #1457 rod. You can see what I mean on the chart on page 15 of this guide.
https://edelbrock-instructions-v1.s3.amazonaws.com/edelbrock/carb-tuning-guide.pdf

The good news is jets and rods can be changed on the fly without needing to disassemble the carb. So first step would be to pull the main rods, jets, and spring and note down what they are. Then order a set of jets and rods to step down leaner. The jets are $12 on summit and the rods are $18 on summit. Or the whole calibration kit with all jets and rods for the 1405 costs about $85

 

[SirRobyn0]

@Bextreme04 I agree with your thoughts, and that the his buddy's engine was probably modified.

 

[iamtherealJayy]

@SirRobyn0 ive been reading that link you sent me and I understand how the change the metering rods, but the jets I thought were inside the carb? I don’t know if I misunderstood something or if I’m misunderstanding myself. Whenever the snow slows down I’m setting the timing. Should I stick with 8-10° mechanical timing? Or should it be more/less? I don’t have a tachometer yet so I can’t do 3000rpm timing. I read the different spring colors, is it going to be like very obvious the different colors or is it going to be kinda like Traxxas shock springs where it’s a line around part of one coil? I’ll check my spring color and once I figure out how to check the jet size I’ll put that on here too. I have a caliper but I dunno how to measure the metering rods. Also his 350 wasn’t very modified that he knew of, I mean it had accessories like electrical fans, chrome this and chrome that, but it didn’t have like a cam lope or anything to it. But hell it could’ve had a 500 lift cam never know, only saw it in person twice, only heard it running once.

 

[iamtherealJayy]

Found a clip of when I saw the el Camino, watching the clip back it might have a cam. Small one tho. This is when he dropped off the carb.

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But as far as I know he didn’t modify the new carb at all.

 

[SirRobyn0]

@iamtherealJayy I on a computer with no sound but I will watch the video later and take my best guess as to whether or not it's been camed.

So the metering rods go into the main jets, effectively making the main jets smaller for cruise operation, as you step down on the gas vacuum is reduced, and the springs in the metering rods over come the vacuum and the metering rods go up allowing more fuel in. How much more fuel is the effect of the size of the metering rod, the tapper of the metering rod and the strength of the spring. Since you can remove the metering rod with the carb top still on the carb it is possible, with the right tools to be able to unscrew and remove the main jets with the top of the carburetor still in place. Remember that the main jets are brass so it's not like they can be pulled out of the bottom of the bowl though the metering rod hole with a magnet. I think guys pull the carb top to change the main jets. Secondary jets back by the secondaries in the bowl so for those it's a requirement to pull the top off the carb. Spring colors for the metering rods will be obvious colors.

I think your mixing up you timing terminology.
Initial timing (sometimes called base timing) is the timing without vacuum or mechanical advance and is what you normally check and set at idle.
Vacuum advance is the amount of advance given by the vacuum can on the side of the distributor.
Mechanical timing is the amount of timing given by the mechanical advance unit inside the distributor, which is controlled by the weights and springs under the rotor.
Total timing is all of that added up.

It would be best to set the initial timing to whatever is listed on the sticker under the hood, if the sticker is gone 8 - 10 is safe and what you should shoot for, especially given that the mark you make no matter how careful you make it is unlikely to be as accurate as a timing tab. Don't worry to much about checking total timing, because it's a stock motor, the distributor is very likely stock, so we wouldn't be looking at total timing for the purposes of tuning, it would just be to verify the mechanical and vacuum advance is working. After you have the initial timing set with the vacuum can disconnected, just give the engine a good rev to see that the mark moves, at least in doing that you'd know it's functional. You have said the inside of the distributor looks good, so as long as you can get the initial timing close I think that would be fine. Part of that is though our discussions of your symptoms this really does seem like a carburetor issue you are fighting, so I'm really not concerned about an advance issue with the distributor, but you do need to set initial.

Let me know if that make sense.

 

[AuroraGirl]

good god man did you change your filter recently or am i mistaking the color of the element for dirt

also, richer than some dumb kids diesel he made to diesel like an idiot, smoke wise
doesnt beat the one day when I had my ford LTD at school and got on the throttle and the next few seconds caused a cloud of smoke not too far unlike a tire in a fire

 

[MelbGMC]

I've had simlar issues with my 1405 Edelbrock Carby and I have tried various setups from the calibration kit.
I have a very mild Crane energiser cam, Edelbrock alloy heads and roller rockers etc.
I'm currently using 120-401 Jets & 068-052 metering rods @ 14 degrees initial timing, it runs pretty well with this setup, but I'm still going to play around with timing and rods etc. It is still running quite rich though with this setup.