AFR was 12.5 WOT, now 13.3

[threewood]

My WOT a/f looks decent now at 12.5 but there is still a lean flat spot/popping right off idle like the accelerator pump isn't working. It's new and squirt when hand actuated. While driving, If I just open the throttles and hold it there it will hold at high 15s, low 16s until I give it more to tip in. I might get in there and raise the float levels a bit.

If I mash the accelerator, it will light the tires without delay.

Holly Sniper is looking better and better.

I've tried the heavy step up spring and it

 

[BSB67]

The rods are stepped. When at high vacuum, the thicker part of the rod is in the jet. When they pop up due to reduced vacuum the thinner tip is in the jet = less restriction, more fuel. I have a calibration kit so I have several to choose from without needing to file them down.

What I think Ron is saying is the rods you installed to richen the cruise may also have leaned out the WOT depending how the rod is stepped.

 

[451Mopar]

Too low a fuel level will make the carb seem lean and tip-in will be really bad.
Need to be careful when swapping rods, the size spread between the thick and thin sections can vary greatly. If you have the rod part numbers, I can look up the step sizes. There is also the issue of summer and winter gasoline blends, and how much ethenol is being added to the fuel.

 

[BSB67]

My WOT a/f looks decent now at 12.5 but there is still a lean flat spot/popping right off idle like the accelerator pump isn't working. It's new and squirt when hand actuated. While driving, If I just open the throttles and hold it there it will hold at high 15s, low 16s until I give it more to tip in. I might get in there and raise the float levels a bit.

If I mash the accelerator, it will light the tires without delay.

Holly Sniper is looking better and better.

I've tried the heavy step up spring and it

Have you simply richened the idle and transition. Light throttle, low speed sag is almost never accelerator pump. What is your initial timing?

Not to offend anyone, but the O2 meter is not the answer. It's a tool. Tune to the best idle, cruise, light acceleration, and WOT it can be. The A/F numbers will be what they are.

 

[68 HEMI GTS]

Promax didn't touch my secondary springs, and before they modded OTHER parts of my carbs, the outboard carbs ALWAYS, under ALL circumstances, EVERY time worked flawlessly!

Doesn’t sound like it works now, so something changed. And you cannot successfully tune a six pack without spring kits.

 

[biomedtechguy]

Not to offend anyone, but the O2 meter is not the answer. It's a tool. Tune to the best idle, cruise, light acceleration, and WOT the best it can. The A/F numbers will be what they are.

No offense taken here. Still, with 3x2s to wrangle, I'll take all the help I can get, and the A/F meter will take a mystery and turn it into hard data.

 

[threewood]

Too low a fuel level will make the carb seem lean and tip-in will be really bad.
Need to be careful when swapping rods, the size spread between the thick and thin sections can vary greatly. If you have the rod part numbers, I can look up the step sizes. There is also the issue of summer and winter gasoline blends, and how much ethenol is being added to the fuel.

I wrote down what rods, but both power mode and cruise are 2 steps richer on the rods I swapped in using the stock primary jet size. I'll see which ones they are and they are paired with pink springs.

Initial timing is 22 / total 36, vacuum advanced hooked up. A/F at idle is 13.4 - 13.9.

 

[BSB67]

I wrote down what rods, but both power mode and cruise are 2 steps richer on the rods I swapped in using the stock primary jet size. I'll see which ones they are and they are paired with pink springs.

Initial timing is 22 / total 36, vacuum advanced hooked up. A/F at idle is 13.4 - 13.9.

What rod numbers

 

[383man]

The rods are stepped. When at high vacuum, the thicker part of the rod is in the jet. When they pop up due to reduced vacuum the thinner tip is in the jet = less restriction, more fuel. I have a calibration kit so I have several to choose from without needing to file them down.

That's why I said years ago and I mean in the 70's when you did not have all these kits full of metering rods to use. So we modified our own. Like we would put wire in the IFR to lean them out some as no carbs had screw in idle bleeds and IFR in the 70's. Ron

 

[threewood]

What rod numbers

6337 rods, stock primary jets.

Pulled the top off, adjusted floats a bit higher, blew out the idle mix passages, adjusted the account pump for best squirt, richened out the idle mix. Fuel pressure is set at 6psi

I called Edelbrock and there is no adjustment specs for the accelerator pump. Told them what was going on and they said check timing and take the carb apart for possible debris in the passages.

Drove it today and there is still a lean surge right after tipping the throttle in. Not all the time but enough to notice the a/f gauge go lean and stay there until I give it more gas.

I guess I need to drive it with a vacuum gauge hooked up and run my fuel pressure gauge to the windshield to see what it's doing.

 

[BSB67]

6337 rods, stock primary jets.

Pulled the top off, adjusted floats a bit higher, blew out the idle mix passages, adjusted the account pump for best squirt, richened out the idle mix. Fuel pressure is set at 6psi

I called Edelbrock and there is no adjustment specs for the accelerator pump. Told them what was going on and they said check timing and take the carb apart for possible debris in the passages.

Drove it today and there is still a lean surge right after tipping the throttle in. Not all the time but enough to notice the a/f gauge go lean and stay there until I give it more gas.

I guess I need to drive it with a vacuum gauge hooked up and run my fuel pressure gauge to the windshield to see what it's doing.

It sounds like you're looking at all the right stuff. The problem will not be fuel pressure, so you can skip that, at least for this symptom.

Have you tried opening up the idle mixture screws. If not, just try it and see what happens.

Finally, someone on here posted recently that he discovered that on his Edelbrock carb that the pump plunger was not retracting far enough for the fuel to refill the pump reservior. Something else to maybe look at.

 

[threewood]

It sounds like you're looking at all the right stuff. The problem will not be fuel pressure, so you can skip that, at least for this symptom.

Have you tried opening up the idle mixture screws. If not, just try it and see what happens.

Finally, someone on here posted recently that he discovered that on his Edelbrock carb that the pump plunger was not retracting far enough for the fuel to refill the pump reservior. Something else to maybe look at.

I adjusted the pump arm (shortened) to raise the pump up a bit. There is no spec for height. I'm on the hole closest to the carb body. That and raising to bowl level should give it plenty of fuel.

I can try opening the mixture more. It is at 1 3/4 turns out.

 

[miller]

In the day, I wouldn't even try to tune a carb, without air temps 70-75 degrees, to get a good average dry tuning day. Seemed to cover all bases.

 

[BSB67]

I adjusted the pump arm (shortened) to raise the pump up a bit. There is no spec for height. I'm on the hole closest to the carb body. That and raising to bowl level should give it plenty of fuel.

I can try opening the mixture more. It is at 1 3/4 turns out.

So what I believe the guy observed was even with everything "properly" adjusted the pump plunger was not retracting enough to expose the pump reservoir slot to let the fuel in. I think he had to bend the linkage to get it to work properly. Just something to check.

The opening of the idle mixture screws is just a test. Open them each a half turn, check your A/F, presumably it will be richer, and go for a ride. It may, or may not help. But it's just a test. At this point my gut tells me you'll probably need to open the idle feed restriction.

 

[threewood]

So what I believe the guy observed was even with everything "properly" adjusted the pump plunger was not retracting enough to expose the pump reservoir slot to let the fuel in. I think he had to bend the linkage to get it to work properly. Just something to check.

The opening of the idle mixture screws is just a test. Open them each a half turn, check your A/F, presumably it will be richer, and go for a ride. It may, or may not help. But it's just a test. At this point my gut tells me you'll probably need to open the idle feed restriction.

I removed the carb and went through it again. I did find pieces of debris on the inlet screens which I think could have caused enough of a restriction to lean it out. Everything else was clean and correct. I swapped back in my 1 step richer rods (cruise/wot) and went back to my original secondary jets. I set the mixture screws for high idle minus a 1/4 turn and it seems to be idling a bit more rich.

On the subject of the pump not being high enough to allow fuel in...I do not believe it is the correct setup. The pump has to be in the well making a seal for any squirt to take place. If it is above the well it just squirts back into the fuel bowl. With the design, after the pump squirts it retracts back up. In doing so it pulls the check valve shut and will draw fuel past the one-way rubber seal on the pump with the vacuum created below the seal.

I also adjusted my timing and swapped in a distributor rebuilt by Halifaxhops. It is now set at 22/36. Took it out for a drive and no lean popping or surging. It does bump up to 15 when pulling away from a light under partial throttle. WOT had me at 12.8 which is better and it seemed more consistent.

I'll drive it around again tomorrow and see if stays the same. Also, it's kind of neat to drive around for a while and still have the air cleaner lid cold to the touch. The six pack hood is neat

 

[69 GTX]

Amazing how much cool air coming in through the hood helps. Sounds like you have your carburetor mastered. I never could get the hang of the needles for jets thing so I always went with Holleys. Everything seems to have a jet for adjustment on them so it's easier for me. Well at least we'll see when I try my hand at 3x2........

 

[BSB67]

I removed the carb and went through it again. I did find pieces of debris on the inlet screens which I think could have caused enough of a restriction to lean it out. Everything else was clean and correct. I swapped back in my 1 step richer rods (cruise/wot) and went back to my original secondary jets. I set the mixture screws for high idle minus a 1/4 turn and it seems to be idling a bit more rich.

On the subject of the pump not being high enough to allow fuel in...I do not believe it is the correct setup. The pump has to be in the well making a seal for any squirt to take place. If it is above the well it just squirts back into the fuel bowl. With the design, after the pump squirts it retracts back up. In doing so it pulls the check valve shut and will draw fuel past the one-way rubber seal on the pump with the vacuum created below the seal.

I also adjusted my timing and swapped in a distributor rebuilt by Halifaxhops. It is now set at 22/36. Took it out for a drive and no lean popping or surging. It does bump up to 15 when pulling away from a light under partial throttle. WOT had me at 12.8 which is better and it seemed more consistent.

I'll drive it around again tomorrow and see if stays the same. Also, it's kind of neat to drive around for a while and still have the air cleaner lid cold to the touch. The six pack hood is neat

Good to know on the pump.

If your air temp is cool and your off idle sag is gone, your probably close. Make sure the engine is hot when doing all of your testing or you'll be chasing after a moving target.

Thanks for the update. Keep us posted.

 

[hangn0ut]

I removed the carb and went through it again. I did find pieces of debris on the inlet screens which I think could have caused enough of a restriction to lean it out. Everything else was clean and correct. I swapped back in my 1 step richer rods (cruise/wot) and went back to my original secondary jets. I set the mixture screws for high idle minus a 1/4 turn and it seems to be idling a bit more rich.

On the subject of the pump not being high enough to allow fuel in...I do not believe it is the correct setup. The pump has to be in the well making a seal for any squirt to take place. If it is above the well it just squirts back into the fuel bowl. With the design, after the pump squirts it retracts back up. In doing so it pulls the check valve shut and will draw fuel past the one-way rubber seal on the pump with the vacuum created below the seal.

I also adjusted my timing and swapped in a distributor rebuilt by Halifaxhops. It is now set at 22/36. Took it out for a drive and no lean popping or surging. It does bump up to 15 when pulling away from a light under partial throttle. WOT had me at 12.8 which is better and it seemed more consistent.

I'll drive it around again tomorrow and see if stays the same. Also, it's kind of neat to drive around for a while and still have the air cleaner lid cold to the touch. The six pack hood is neat

Been a while since I messed with a Carter carb. Never messed with the edelbrock version. Sounds like carb still has debris in it. Have you been removing the boosters to clean them? Blast them with brake cleaner using the plastic straw pushed into the passages and watch where the cleaner comes out. Hold them up to a light to verify the passages are clear. Make sure the gasket is good and the booster sits properly. Good luck.

 

[threewood]

Amazing how much cool air coming in through the hood helps. Sounds like you have your carburetor mastered. I never could get the hang of the needles for jets thing so I always went with Holleys. Everything seems to have a jet for adjustment on them so it's easier for me. Well at least we'll see when I try my hand at 3x2........

I'm the opposite. I've always had a hard time tuning Holley. Edelbrock / Carters make more since to me and I like being sble to tune them without draining the bowls everytime.

Been a while since I messed with a Carter carb. Never messed with the edelbrock version. Sounds like carb still has debris in it. Have you been removing the boosters to clean them? Blast them with brake cleaner using the plastic straw pushed into the passages and watch where the cleaner comes out. Hold them up to a light to verify the passages are clear. Make sure the gasket is good and the booster sits properly. Good luck.

Thanks. The carb is clean. Completely broke it down and went through the passages with carb cleaner. On the boosters I did the same and used fine wire in the bleeds and passages. This carb is dual feed and in each float seat there is a screen filter that keeps muck out of the carb.

 

[Crackedback]

Do you have the tuning guide for the EDE?

They have a chart with rod numbers to adjust AFR based on % difference in orfice sizing. Check the Ede site for the PDF.