Can’t figure out carburetor

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Craig Burriss

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FABO Gold Member
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I can’t tell if I’m just doing something really wrong or if something is F’ed up in my carburetor. I’m new to tuning carburetors and never thought turning a screw driver would be so dang hard.
How do I tune the thing if I can’t even get the car to start in the first place?
I have a mild 440 with 10:1 compression, Edelbrick 800 carb, intake, and fuel pump.
My fuel pressure while cranking is 6.5psi.
I’ve set the timing to roughly 10BTDC by finding TDC on cylinder #1 on the compression stroke.
I have confirmed that I have spark while cranking.
My spark plugs are EXTREMELY fouled because evidently the carb was flooding the engine.
I turned the idle mixture screws in about 1 turn each to lean it out some and the car started coughing up smoke out of the carb. I turned the screws back half a turn towards where they were originally and it’s not even attempting to fire now.
I’ve even taken the carb apart to see if anything was clogged or broken but everything looked normal.
I feel like me and my car are going to wear out this forum we have so many problems I can’t figure out.
 
I can’t tell if I’m just doing something really wrong or if something is F’ed up in my carburetor. I’m new to tuning carburetors and never thought turning a screw driver would be so dang hard.
How do I tune the thing if I can’t even get the car to start in the first place?
I have a mild 440 with 10:1 compression, Edelbrick 800 carb, intake, and fuel pump.
My fuel pressure while cranking is 6.5psi.
I’ve set the timing to roughly 10BTDC by finding TDC on cylinder #1 on the compression stroke.
I have confirmed that I have spark while cranking.
My spark plugs are EXTREMELY fouled because evidently the carb was flooding the engine.
I turned the idle mixture screws in about 1 turn each to lean it out some and the car started coughing up smoke out of the carb. I turned the screws back half a turn towards where they were originally and it’s not even attempting to fire now.
I’ve even taken the carb apart to see if anything was clogged or broken but everything looked normal.
I feel like me and my car are going to wear out this forum we have so many problems I can’t figure out.
It's always nice to know where you're at. What I do with a new carburetor is or new to me is count how many turns it takes to turn them all the way into the right. Make a note of each one. That way you know where you started. Do not over tighten them just to where it stops. That's extremely important you can damage them if you get too or even a little aggressive. Generally the book will say one and a half to two terms out to start just so you know..
Google the Edelbrock owners manual if you don't have one and download it and read the tuning instructions. Then reread them again...
 
Idle mixture screws out of adjustment will not prevent the car from starting. If carb is flooding, then check the float level. Have you removed the distributor? 180* off?
 
I can’t tell if I’m just doing something really wrong or if something is F’ed up in my carburetor. I’m new to tuning carburetors and never thought turning a screw driver would be so dang hard.
How do I tune the thing if I can’t even get the car to start in the first place?
I have a mild 440 with 10:1 compression, Edelbrick 800 carb, intake, and fuel pump.
My fuel pressure while cranking is 6.5psi.
I’ve set the timing to roughly 10BTDC by finding TDC on cylinder #1 on the compression stroke.
I have confirmed that I have spark while cranking.
My spark plugs are EXTREMELY fouled because evidently the carb was flooding the engine.
I turned the idle mixture screws in about 1 turn each to lean it out some and the car started coughing up smoke out of the carb. I turned the screws back half a turn towards where they were originally and it’s not even attempting to fire now.
I’ve even taken the carb apart to see if anything was clogged or broken but everything looked normal.
I feel like me and my car are going to wear out this forum we have so many problems I can’t figure out.


That's too much fuel pressure. Cut that down to about 5 psi and that's a start. Get your initial up to 18-20 degrees and then you can start tuning.

What cam, ignition and pugs are you using?
 
Idle mixture screws out of adjustment will not prevent the car from starting. If carb is flooding, then check the float level. Have you removed the distributor? 180* off?
When setting the timing, I made sure the rotor was pointing towards the #1 cylinder. I’ll check float level when I get home tomorrow and find the book that came with the carb.

That's too much fuel pressure. Cut that down to about 5 psi and that's a start. Get your initial up to 18-20 degrees and then you can start tuning.

What cam, ignition and pugs are you using?
Assuming I need a fuel pressure regulator to do that unless there’s some trick I don’t know.
Cam specs posted below
I a Summit brand electronic ignition system just like the factory style that came with my 440, and an MSD coil.
I have a German Shepherd not a Pug. But my plugs are E3 (I have them in all of my vehicles)
FFB8D9E6-6880-4BA4-AED2-3565465EBDF4.jpeg
 
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Since you motioned plugs were extremely fouled, Replace plugs, set carb at factory spec, make sure your getting gas without dumping a bunch of fuel, give a couple of pats, and a shot of quick start, and turn the key. once it fires, time the car into spec.
 
When setting the timing, I made sure the rotor was pointing towards the #1 cylinder. I’ll check float level when I get home tomorrow and find the book that came with the carb.


Assuming I need a fuel pressure regulator to do that unless there’s some trick I don’t know.
Cam specs posted below
I a Summit brand electronic ignition system just like the factory style that came with my 440, and an MSD coil.
I have a German Shepherd not a Pug. But my plugs are E3 (I have them in all of my vehicles)
View attachment 1715419695


That cam will take 18-20 degrees initial and yes, you need to regulate the fuel pressure down to 5 max. 4.5-5 is where it should be.

Because I'm old, 39 years old in case Jpar sees this) I forgot to ask what fuel pump?
 
10 BTDC and 4-5psi will start car, set from there. Belching smoke and fire is not good. confirm spark plug routing for an RB (CCW) 18436572. Popping carb sounds like firing order/plug wiring is wrong. 5/7 are next to each other, common to mix up.
upload_2019-11-6_15-45-21.jpeg


See if boosters are dripping fuel at idle (fuel level too high or too much pressure), careful looking into carb during idle, use a mirror or video it with cell phone. check Edelbrock for a missing vacuum port plug on rear base, they come with it unscrewed rolling around the box sometimes.
 
10 BTDC and 4-5psi will start car, set from there. Belching smoke and fire is not good. confirm spark plug routing for an RB (CCW) 18436572. Popping carb sounds like firing order/plug wiring is wrong. 5/7 are next to each other, common to mix up.
View attachment 1715419700

See if boosters are dripping fuel at idle (fuel level too high or too much pressure), careful looking into carb during idle, use a mirror or video it with cell phone. check Edelbrock for a missing vacuum port plug on rear base, they come with it unscrewed rolling around the box sometimes.
I checked the firing order probably 9 times so it can’t be that. I sealed that plug into the back with thread sealer a couple years ago so maybe it needs to be resealed.
 
Just pinch the carb fuel line off and let it pull it dry during idle. Does the idle improve when the fuel level/pressure falls? Got a vacuum guage? I had similar 284/.484 Mopar cam in a 340 and got the idle down to 600 in gear w/14" so its not that radical.
 
Tomorrow I’ll grab some new plugs on the way home and just start over. I’m hoping I can at least get it to idle right by this weekend
 
Without a choke; a cold engine takes gob and gobs of gas to get started . Fill the float bowls and shut the pump off, or as said pinch the line if a mechanical pump. Crank the timing up also as said.
Put a half a teaspoon of oil in every cylinder, and let it sit while you install the new plugs.
With the distributor properly installed etc, I would just hold the gas pedal down so that the primaries are at least about 1/4 to 1/2 open, and then crank it til it starts firing. If it gets better with every revolution keep going, holding the pedal steady until AFTER it starts, cleans itself out, and begins to rev up.
But if it doesn't get better, I'd keep cranking and stabbing the gas pedal, until it comes to life.
Some people say continuous cranking like that can shorten the life of the starter. Take your pick; either the cam dies for lack of break-in lube, or way in the future the starter fails. Starters are cheap compared to a new cam and lifters, installed. Besides new brushes will fix her right up. I've got or had cars with 40/50 year old starters on them. Brushes and/or drives is all they ever need.
Personally, I wouldn't even change the plugs; I'd just wash them and blow-dry them.
 
10 BTDC and 4-5psi will start car, set from there. Belching smoke and fire is not good. confirm spark plug routing for an RB (CCW) 18436572. Popping carb sounds like firing order/plug wiring is wrong. 5/7 are next to each other, common to mix up.
View attachment 1715419700

See if boosters are dripping fuel at idle (fuel level too high or too much pressure), careful looking into carb during idle, use a mirror or video it with cell phone. check Edelbrock for a missing vacuum port plug on rear base, they come with it unscrewed rolling around the box sometimes.


That cam he has is 302 on the seat. That's a long, slow ramp. That cam will act like it's much bigger than it really is.

10 BTDC is too damn slow to get it started. I rather see 30 intial than that.

He just needs to stop, regroup and then start changing things after he gets the fuel pressure and timing correct.
 
You have some good suggestions here, one thing I wonder is if you had it running with that cam before the carb swap. In other words, did you degree the cam, if not did you use one of those 3 keyway timing sets? I have seen people get confused with what dot to use .

I would follow the other suggestions, timing and fuel pressure before digging in to this.
 
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You have some good suggestions here, one thing I wonder is if you had it running with that cam before the carb swap. In other words, did you degree the cam, if not did you use one of those 3 keyway timing sets? I have seen people get confused with what dot to use .

I would follow the other suggestions, timing and fuel pressure before digging in to this.
Yes it was running decent at one point. Then something happened to my distributor pickup and it wouldn’t run. Now that I’ve fixed that the carb is being a PITA
 
Are you using a factory pick-up?
Cuz they are color-coded; your SBM PU needs to have one orange wire for CW rotation.
The slanty/440 pick up is wired for CCW rotation.. It will still send sparks at low rpm and will run, sorta, but as soon as you try to bring up the rpm, the spark has a mind of it's own. I think this one IIRC has a purple wire; in any case don't use a purple-wired PU.
 
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Are you using a factory pick-up?
Cuz they are color-coded; your SBM PU needs to have one orange wire for CW rotation.
The slanty/440 pick up is wired for CCW rotation.. It will still send sparks at low rpm and will run, sorta, but as soon as you try to bring up the rpm, the spark has a mind of it's own. I think this one IIRC has a purple wire; in any case don't use a purple-wired PU.
The entire ignition system is the big block style. I think the only thing keeping it from running is me not knowing how to properly set everything.
 
So I had the firing order correct... at least it would have been if the distributor turned clockwise.
I was standing there just looking at the engine thinking “WHY?”. And then it hit me. I swapped the wires around and it fires up now. All of you were right when you said it sounds like the plug wires are mixed up.
When my distributor pickup went bad I basically replaced everything in the ignition system and evidently put the wires on backwards.
Sorry for wasting everyone’s time with something so simple.
I’ve learned more on this car than I have in my 2 years of college so far lol.

Thank’s everyone.
 
The entire ignition system is the big block style. I think the only thing keeping it from running is me not knowing how to properly set everything.
Yeah sorry, I forgot.
With the BB factory ignition, your PU should have one violet wire. but water under the bridge now......
 
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