I've been chasing a "bog" at full throttle in a 305 with a 700r4 I put in a s10 I went as far as buying a new qudrajet just to have the same issue my air/fuel guage says my motor is going way too rich at full throttle I'll definitely try this ... I'm stumped at this point
geez, have not worked on one of these in 30 years, maybe more. Checked out your channel, Subscribed up. I do all weird stuff on my channel. Garden, ATV, car repairs, blah blah blah. Just imported a RHD wagon from Kobe, Japan. 04' Subaru Forester Cross Sports, 2.0L turbo, 5 speed. ZERO RUST! Easy Wagon'ator to work on. Funny, bolts come right out, no huss, no fuss. Stumpr1
My quad . When revving in neutral , the secondaries open slightly . Are the doors too tight ?I have a pretty good bog when I stab it from a stand still but runs fine otherwise
Completely normal for the secondaires to barely open while revving in neutral. A bog usually indicates the secondary air door is opening too soon or too easy. The choke-brake (diaphragm) located at the passenger side front of the carb should have a rod that leads back to the secondary air door. The choke-brake should hold that door closed ( tight) while idling (high intake vacuum) and bleed-off slowly when you smash the throttle. Some carbs even have a secondary choke-brake located at the passenger rear of the carb with rods leading to the secondary air door. They effectively do the same thing as pertaining to the air door, that is, slow it's ability to open causing fuel to flow out of the secondary nozzles -thus covering up the "bog" you are feeling. Have a good look at all of this and make sure it's all operating as designed. It's possible someone put an aftermarket choke-brake on that's bleeding off too quick. It should take a good 2-3 seconds for that choke-brake (diaphragm) to bleed off if you simply remove the vacuum hose at an idle. If it flys open, that's likely the problem. The opening rate is controlled by the tiny hole where the vacuum hose connects.
Good clear video. I realize it is 3 years old. Nine years ago I bought a 1983 El Camino Conquista. I finally started restoring it. OEM it had a CCC 305 and TH200-4R. Somewhere along the line somebody had put a non CCC 305 (no O2 port in stock cast iron exhaust manifold and vacuum advance distributor), and a TH350 but swapped the OEM E4ME CCC Quadrajet and proceeded to muck up the E4ME to work without CCC. That was an incredible mouse hunt all of it's own to figure all that out. Needless to say, there have been more than several mouse hunts to get this thing running right. I put an O2 on it, and a brand spanking new E4ME. There are no markings on the E4ME, got it off fleabay so I am assuming it's a knockoff. I was surprised at how well it ran at first bolt on, much better than the mucked up OEM (yes I will rebuild it one day). Only two things needed adjusted on the new one (although I took it apart and checked everything). First was moving the throttle to accelerator linkage to the lower hole (it has two) on the accelerator pump lever and bending it to achieve 0.48V at the middle wire TPS (cannot get to 0.48 at upper hole). It now meters correctly throughout the rpm range. Second adjustment is going to be this air valve adjustment. It has the dreaded "quadra bog" at WOT. Goes way rich and stumbles at all timing settings. I have a temporary O2 meter in the cab with me so I know what it is doing at all times while I get it tuned. TPS voltage is correct at WOT. I have yet to do this air valve spring adjustment so I will find out tomorrow if it is even there on this brand new no markings E4ME, but your video explains it so well, I want to give you a big THANK YOU! Thank you so much. I enjoy clear informative videos like yours that convey critical need to know information. I have the E4ME Instruction Sheet.pdf (C Technut Co. 1985, 50-589-3) and it shows all the critical E4ME/E4MC adjustments including this one. In the data table it shows 7/8 turn for a 305, 9/16 for a 231, 5/8 for a 252, 1/2 for a 307 and 350. No other engines specified and only 1980, 81 and 82. Chevy, Olds and Buick. I wanted to post this extra info in case it helps you or someone else. Needless to say, I'll be backing this one off, if it even has the set screw and adjustment screw. Also, I will note what it is currently set at. I seriously doubt the set screw will be a T10. All "settings" screws on this so far have been slotted. Will find out tomorrow. THANK YOU
great video, I'm going to experiment with mine. on my 355 sbc hot rod engine, it's got high compression and a decent roller cam, and when i open my secondaries, no bog but also no burst of additional power either. mine might be too tight
Thank you for this video. I own a 84 Buick LeSabre with olds 307. My secondary will not open at WOT im gonna attempt to adjust it the 4 bbl on this carburetor has never worked right. U can tao it open and it wint shut back all the way. It will work it i simultaneously open the secondary and open to full throttle. Gonna give it a try 👍
There's a little "lock-out" flipper behind the choke that prevents the secondaries from opening until the choke is completely open. Occasionally that flipper doesn't move far enough (even with the choke fully open), and prevents the secondaries from opening. You can remove that lock-out flipper entirely and just be aware that getting into the secondaries on a cold engine may cause it to "bog" a bit. It requires partially removing the choke housing in order to remove the flipper.
@@mark_osborne oh yes i saw another video about that and my choke was not working correctly for 2 reasons. 1 the front vacuum break was bad replaced it and the choke heater needed adjusting. But those heaters i read were not adjustable some were some weren't mine wasnt because if a notch were it mounted on the housing. I made the decision to file it down to be able to ajust it. It worked. After all that i realize ld my secondaries still were working even with the lockout tab being cleared. Im gonna follow your directions on adjusting it. Can it be down with out taking the top of carb off ?? Thanks 👍
@@hunterriley9904 If you're real careful, you can remove the choke spring and take the screws out that hold the choke spring housing to the body of the carb, and very carefully pull it away just enough to allow that flipper to come off of the stud it's riding on. If you pull it too far out, the mechanism that drives the choke rod will disengage and you'll be forced to reattach it and that requires removing the top of the carb - but that isn't awful
@@mark_osbornewell i attempted to adjust the secondary air door with no luck. I was able to loosen the set screw and attempt it but the air door isn't operating correctly. It has tension about 1)4 of the way open then flaps open the rest of the way its tight like theres a restriction i cant tell if its in the spring or the shaft. I was able to get it a little better with a sprist if wd40 and move it back and forth for a few minutes but still the same. I took a short video im gonna post it would like your opinion on what the problem may be. Thanks a bunch 👍
Thanks for the videos! I am currently looking into rebuilding my q-jet on my 1984 chevy ramp truck. It has a 454 and a 4 speed manual. A couple of questions for you: 1) do you have a rebuild kit part number or manufacturer you recommend? 2) where do I find the secondary air door setting for a 454? Thank you.
Look on the driver's side of the carb near the secondaries, there's a long GM number (something like 17084502). Go to Rockauto, search carb rebuild kits for an '84 3/4 or 1 ton truck. You'll see a list of about 8 (I just looked). They show the carb numbers associate with the kit in the listing. It has been my experience the directions will give you the secondary air door adjustment. If they don't, try 3/4's of a turn from just closed (like I show in the video). If it's rich, back it off an 1/8 of a turn. If it's lean, do the opposite.
Hey! Really enjoy the practical info. We’re building a pretty custom adventure rig and these carbs have me intrigued. Curious how they perform or can be adjusted to do so in off-camber/incline/decent? I would really like to run a carb vs efi. Especially if I am able to tune it proper.
That is a good question, I'm not sure how steep they'll go without dumping raw fuel through the nozzles ... but I'm guessing all of 30 degrees. You could always grab one, fill the float bowl with fuel and tip it up and determine it's maximum angle. There's no reason it won't work other than that.
Air flow. To be clear, the lower butterfly doors are opened mechanically through linkage that is attached to the primary butterfly doors, and as air flow increases (with RPM), the secondary air doors will slowly be sucked open against the spring that is normally keeping them closed. The shaft is off-center, so the larger surface area (side) will win
Metric CID specs are rounded off so as to not be described so precisely. 1 liter of volume is 60.5 cubic inches. Yet they call a 302, 305, and a 307 a 5.0. It is done with rear end ratios also, so a 4.10 and 4.11 are virtually the same. Just in case automotive terms weren't ambiguous enough.
@@mark_osborne had a customers vehicle here and was having that bog when I would punch the throttle and sure enough secondary butterfly had no tension at all.
I've been chasing a "bog" at full throttle in a 305 with a 700r4 I put in a s10 I went as far as buying a new qudrajet just to have the same issue my air/fuel guage says my motor is going way too rich at full throttle I'll definitely try this ... I'm stumped at this point
geez, have not worked on one of these in 30 years, maybe more. Checked out your channel, Subscribed up. I do all weird stuff on my channel. Garden, ATV, car repairs, blah blah blah. Just imported a RHD wagon from Kobe, Japan. 04' Subaru Forester Cross Sports, 2.0L turbo, 5 speed. ZERO RUST! Easy Wagon'ator to work on. Funny, bolts come right out, no huss, no fuss. Stumpr1
My quad . When revving in neutral , the secondaries open slightly . Are the doors too tight ?I have a pretty good bog when I stab it from a stand still but runs fine otherwise
Completely normal for the secondaires to barely open while revving in neutral. A bog usually indicates the secondary air door is opening too soon or too easy. The choke-brake (diaphragm) located at the passenger side front of the carb should have a rod that leads back to the secondary air door. The choke-brake should hold that door closed ( tight) while idling (high intake vacuum) and bleed-off slowly when you smash the throttle. Some carbs even have a secondary choke-brake located at the passenger rear of the carb with rods leading to the secondary air door. They effectively do the same thing as pertaining to the air door, that is, slow it's ability to open causing fuel to flow out of the secondary nozzles -thus covering up the "bog" you are feeling. Have a good look at all of this and make sure it's all operating as designed. It's possible someone put an aftermarket choke-brake on that's bleeding off too quick. It should take a good 2-3 seconds for that choke-brake (diaphragm) to bleed off if you simply remove the vacuum hose at an idle. If it flys open, that's likely the problem. The opening rate is controlled by the tiny hole where the vacuum hose connects.
Good information
How much tension for a big block? Got a Buick 455 and the secondaries are all sorts of loose giving me some hesitation at harder throttle
Tighten it up 1/4 turn and see what happens
Good clear video. I realize it is 3 years old. Nine years ago I bought a 1983 El Camino Conquista. I finally started restoring it. OEM it had a CCC 305 and TH200-4R. Somewhere along the line somebody had put a non CCC 305 (no O2 port in stock cast iron exhaust manifold and vacuum advance distributor), and a TH350 but swapped the OEM E4ME CCC Quadrajet and proceeded to muck up the E4ME to work without CCC. That was an incredible mouse hunt all of it's own to figure all that out. Needless to say, there have been more than several mouse hunts to get this thing running right. I put an O2 on it, and a brand spanking new E4ME. There are no markings on the E4ME, got it off fleabay so I am assuming it's a knockoff. I was surprised at how well it ran at first bolt on, much better than the mucked up OEM (yes I will rebuild it one day). Only two things needed adjusted on the new one (although I took it apart and checked everything). First was moving the throttle to accelerator linkage to the lower hole (it has two) on the accelerator pump lever and bending it to achieve 0.48V at the middle wire TPS (cannot get to 0.48 at upper hole). It now meters correctly throughout the rpm range. Second adjustment is going to be this air valve adjustment. It has the dreaded "quadra bog" at WOT. Goes way rich and stumbles at all timing settings. I have a temporary O2 meter in the cab with me so I know what it is doing at all times while I get it tuned. TPS voltage is correct at WOT. I have yet to do this air valve spring adjustment so I will find out tomorrow if it is even there on this brand new no markings E4ME, but your video explains it so well, I want to give you a big THANK YOU! Thank you so much. I enjoy clear informative videos like yours that convey critical need to know information.
I have the E4ME Instruction Sheet.pdf (C Technut Co. 1985, 50-589-3) and it shows all the critical E4ME/E4MC adjustments including this one. In the data table it shows 7/8 turn for a 305, 9/16 for a 231, 5/8 for a 252, 1/2 for a 307 and 350. No other engines specified and only 1980, 81 and 82. Chevy, Olds and Buick. I wanted to post this extra info in case it helps you or someone else. Needless to say, I'll be backing this one off, if it even has the set screw and adjustment screw. Also, I will note what it is currently set at. I seriously doubt the set screw will be a T10. All "settings" screws on this so far have been slotted. Will find out tomorrow. THANK YOU
So interesting - and thanks - great information!
Let us know if you have the adjustment, and if you get it sorted. Thank you
great video, I'm going to experiment with mine. on my 355 sbc hot rod engine, it's got high compression and a decent roller cam, and when i open my secondaries, no bog but also no burst of additional power either. mine might be too tight
Make sure the choke lock-out isn't preventing the secondaries from opening
@@mark_osborne thank you
@@kevinclancy. absolutely, sorry, I just seen your question
Does 1-1/2 turns stand true for the large 472 Cadillac engine (1968)?
I'd try it and see. The tension is also dependent on the metering rod diameter, they work together. If it seems rich, back it off 1/4 turn
Thank you for this video. I own a 84 Buick LeSabre with olds 307. My secondary will not open at WOT im gonna attempt to adjust it the 4 bbl on this carburetor has never worked right. U can tao it open and it wint shut back all the way. It will work it i simultaneously open the secondary and open to full throttle. Gonna give it a try 👍
There's a little "lock-out" flipper behind the choke that prevents the secondaries from opening until the choke is completely open. Occasionally that flipper doesn't move far enough (even with the choke fully open), and prevents the secondaries from opening. You can remove that lock-out flipper entirely and just be aware that getting into the secondaries on a cold engine may cause it to "bog" a bit. It requires partially removing the choke housing in order to remove the flipper.
@@mark_osborne oh yes i saw another video about that and my choke was not working correctly for 2 reasons. 1 the front vacuum break was bad replaced it and the choke heater needed adjusting. But those heaters i read were not adjustable some were some weren't mine wasnt because if a notch were it mounted on the housing. I made the decision to file it down to be able to ajust it. It worked. After all that i realize ld my secondaries still were working even with the lockout tab being cleared. Im gonna follow your directions on adjusting it. Can it be down with out taking the top of carb off ?? Thanks 👍
@@hunterriley9904 If you're real careful, you can remove the choke spring and take the screws out that hold the choke spring housing to the body of the carb, and very carefully pull it away just enough to allow that flipper to come off of the stud it's riding on. If you pull it too far out, the mechanism that drives the choke rod will disengage and you'll be forced to reattach it and that requires removing the top of the carb - but that isn't awful
@@mark_osbornewell i attempted to adjust the secondary air door with no luck. I was able to loosen the set screw and attempt it but the air door isn't operating correctly. It has tension about 1)4 of the way open then flaps open the rest of the way its tight like theres a restriction i cant tell if its in the spring or the shaft. I was able to get it a little better with a sprist if wd40 and move it back and forth for a few minutes but still the same. I took a short video im gonna post it would like your opinion on what the problem may be. Thanks a bunch 👍
You are right there, that last 1/4 turn is everything @@hunterriley9904
Thanks for the videos! I am currently looking into rebuilding my q-jet on my 1984 chevy ramp truck. It has a 454 and a 4 speed manual. A couple of questions for you:
1) do you have a rebuild kit part number or manufacturer you recommend?
2) where do I find the secondary air door setting for a 454?
Thank you.
Look on the driver's side of the carb near the secondaries, there's a long GM number (something like 17084502). Go to Rockauto, search carb rebuild kits for an '84 3/4 or 1 ton truck. You'll see a list of about 8 (I just looked). They show the carb numbers associate with the kit in the listing. It has been my experience the directions will give you the secondary air door adjustment. If they don't, try 3/4's of a turn from just closed (like I show in the video). If it's rich, back it off an 1/8 of a turn. If it's lean, do the opposite.
Hey! Really enjoy the practical info. We’re building a pretty custom adventure rig and these carbs have me intrigued. Curious how they perform or can be adjusted to do so in off-camber/incline/decent? I would really like to run a carb vs efi. Especially if I am able to tune it proper.
That is a good question, I'm not sure how steep they'll go without dumping raw fuel through the nozzles ... but I'm guessing all of 30 degrees. You could always grab one, fill the float bowl with fuel and tip it up and determine it's maximum angle. There's no reason it won't work other than that.
Good info 👍.
Thanks for dropping by !
What opens the secondary air doors, vacuum?
Air flow. To be clear, the lower butterfly doors are opened mechanically through linkage that is attached to the primary butterfly doors, and as air flow increases (with RPM), the secondary air doors will slowly be sucked open against the spring that is normally keeping them closed. The shaft is off-center, so the larger surface area (side) will win
How are those lithium batteries doing?
They are doing great, no issues what so ever. I need to do an update on THAT !..lol
Are secondary air doors the same as secondary air valves??
Yes, I think that is a fair statement
do you need to speed up the vacuum brake mine seems very slow
I've never tried to cross that bridge but I know what you mean. Do you feel you are running a bit rich until it has had a chance to fully retract ?
Was the 305 the 5.0 chevy engine sorry if silly question
Yes
Metric CID specs are rounded off so as to not be described so precisely. 1 liter of volume is 60.5 cubic inches.
Yet they call a 302, 305, and a 307 a 5.0. It is done with rear end ratios also, so a 4.10 and 4.11 are virtually the same. Just in case automotive terms weren't ambiguous enough.
Thanks
Excellent video Buddy!
Thank you so much !
@@mark_osborne had a customers vehicle here and was having that bog when I would punch the throttle and sure enough secondary butterfly had no tension at all.