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Discussion Starter #1
Totally new to engines with carburetors - just picked up a 1968 GTO today.

I can't get the car to stay running unless it's at about 2000 RPM. It will die shortly after starting otherwise. I'm understanding that this is probably the carb not being set right - but from what I can tell, to get the carb set you need the car running and warm - which is difficult to get when it doesn't want to run slowly.

Any clues? Would love a point in the right direction.

Cheers
Mark
 

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Need a lot more info. Carb type? Rebuilt? Ignition type, when was last tune up? Engine Timing? Engine original or rebuilt? Mileage? Ever adjust valves? Check fuel lines, fuel pump, fuel pressure? Fresh fuel? Fuel filter new? Choke? Idle mixture screw setting? Vacuum leak? Power Brakes?

The carb could be the problem, but it may not be. Gotta go step by step.

So give us more info, what you know, and what you may have already done and we will get you going. (y)
 

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Discussion Starter #3 (Edited)
Carb is an Edelbrock - I will double check on what it is specifically. Edit - Edelbrock 8867

The car got restored sometime probably ~20ish years ago. Still the original 400 engine in it, 86K original miles. No clue when it was last tuned. Valves have not been set in a while.

Fuel lines / fuel pump are my next checks. No clue on filters. Choke is automatic from the carb, so far as I can tell.

I do not think there are any vaccuum leaks, but I need to check. Does not have carb assisted brakes, as it were.

Thanks Jim!
 

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Or a malfunctioning choke or not set right choke, when an engine is cold the choke and fast idle cam, which is part of the choke mechanism make the car run richer and with more throttle until it warms up. So on start up the choke closes, and the fast idle cam engages, and RPM’s should be in the 1200 to 1500 range.

as the car warms the choke spring moves to allow the choke to gradually open.

Now this may be other things like the guys said, but are you starting with the proper procedure to engage the choke when starting? If not and then you may be racing the motor with the accelerator pedal to keep it at 2000 Rpm’s where it then warms up.

so start where you are at at cold startup, pump the gas pedal two to three half pumps, the last one pump all the way to the floor to set the choke. Now have some patience wait 30 seconds or so and let the gas settle in over the valves, then crank it without pumping the pedal. If it starts let it run to warm up, if it almost starts crank again but stay off the pedal in Initially. As it warms after a few minutes you can pump the pedal halfway down to release the fast idle cam, and the car will idle down.

you can also do checks on the choke and the accelerator pump by watching them and the choke may need resetting, but it sounds like you may be trying to run a cold engine with no choke .....
 

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When you press all the way to the floor on the last pump , don’t hold it down release it and that will set the choke....
 

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All good tips. First off, you must have fresh gas. If it has been sitting for more than a month or so, the gas is probably soured if ethanol laced gas. If it is the original engine, probably has 10/10.5 compression and this will be a problem on pump gas unless you are at a higher altitude where air is thinner and higher compression is needed.

As stated, I would remove the air cleaner and peer into the carb. Look at the choke first and note its setting, closed, open, or something in between. Then put the gas pedal to the floor 1 time to set the choke - which should be fully closed. If it happens to be fully opened, then that may be your first issue. Fully open on a cold engine could cause you to require higher RPM's to keep it running until heat from the manifold crossover warms up the carb from underneath. If it is fully shut, I like to push it open to see how much tension is on the choke in keeping it closed. I am not very versed in electric chokes, but on a manual choke, the spring tension of the bi-metal spring found in the choke housing on the side of the carb can be too tight. It can be adjusted a little looser to reduce tension and allow the choke to open more freely. If the choke is too tight, it is possible that little air is getting through and revving it up may be using the manifold vacuum to pull it open enough to keep it running.

Next you want to use a light and look down the throat of the front/primary barrels of the carb with the choke open (manually by hand if needed). Then looking into the carb, manually open the carb as if you were putting the gas pedal to the floor. You should see 2 good solid streams of gas squirt into the primaries- one in each primary bore. This is assuming the carb bowl is filled with gas. If you do not see this, then you may have carb issues.

A little research says your "8867" carb is an Edlebrock #1405 fitted with an electric choke, or possibly the #1406 which came with the electric choke installed. It is the AFB style and is 600CFM's which is really too small for the 400CI. The 750CFM would be what you want.

That said, what manifold as yours would not be the factory cast iron Q-jet intake unless you are using an adapter? Let us know as this could be important. If using an adapter, I have seen wrong adapters/gaskets used which could allow for a big vacuum leak that you won't readily see. Then we can go from there. (y)
 

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Discussion Starter #8
So, upon doing a touch more research (and finding more numbers...) the carb appears to be a #1407. It does not appear to be an electric choke (at least I can't find any wires running to the carb...)

Edit: Regarding gas - It had gas in it from the previous owner that I drove around with successfully for about 25 minutes yesterday. I filled up with premium, which is what the last owner had done as well. Had these problems approx. 20 minutes after filling up, but I did have an electrical issue first (burnt off wire on the coil) that shut me down.

I did find one problem in that the rubber cap for the driver's side vacuum port was cracked. I've covered it electrical tape at the moment for a test fix. I did also find a wire burnt off the coil from the ignition that I fixed - but still having the issue. I'll follow what you just said Jim in a second and see what I can make out.

Here's a few pics of the carb, if it helps. Note that the idle screws are set all the way in and out depending on each as I was attempting to get things set - however this problem exists no matter where the screws are set.


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133856
133857
133858
 

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Right on Jim, .......now there is no choke mechanism on that carb, the choke flap is on the top, the black flap, but the mechanism to make it work, an electric choke is a simple one and could be added. Or a simple manual choke could be added, but you have to run the cable to the dash. A new carb may be easier actually , by the time you rebuild this and buy a choke etc.

but your hard starting could just be lack of a choke. You have to also fix that coil wire and vacumn leak, and not with electrical tape.

but you will get it and it is runnning, so stay with it! Good luck and let us know how you do!
 

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Discussion Starter #10
All -

Coil wire is fixed. Still have the BS patch on the vacuum port for now - next time I run to the shop I'll get that fixed.

I am fairly certain the problem is the choke not being set right as it sits. To my understanding, this carb should have an automatic mechanical choke set only by the gas pedal.

At this time, if you press the gas pedal all the way, the choke remains vertical (all the way open). The choke can easily be "flopped around" by hand - it does not seem like there is any spring pressure behind it, if at all.

My roommate got home today and I had him hold it almost all the way closed and she fired up like a champ - was able to set the idle mixture and idle speed. I dropped it down to about 800 RPM, but didn't go lower just in case.

Took it for a drive - she runs great - but coming out of gear (4 speed manual) and dropping into idle causes it to immediately die. I'm fairly certain that it's the vacuum drawing the choke shut, preventing airflow and choking the engine off.

I'm going to take a peek at the carb manual and see if I'm missing a bit of linkage or spring or etc. - but if anyone has any guidance, I am all ears!
 

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OK, no choke. The 1407 is the 750CFM carb. Photo shows the 1406 and how the electric choke is attached - and you will need a 12v wire/source.

Jegs has them for $72.00 and you can read the PDF instructions to see what you are getting into.

I see a carb adapter and what looks like staining on the right side under the adapter. I see staining at the front of the carb itself. What Edelbrock intake is that? I am assuming the intake is for a Quadra-Jet and the previous owner went with the AFB, or the carb intake bores are for the smaller 600CFM and the slightly larger secondary throttle plates may have been hitting?

What are the vacuum hoses on the front of the carb? One is for the PCV valve that fits into the valley pan. What is the other for?

To adjust idle screws, initial setting is to turn them in gently until they stop - don't crank down on them. Then back each one out 2 1/2 turns. That will get you in the ball park and fine tuning can be done once the engine is running and warmed up.

The carb most likely needs a complete rebuild. Adding the electric choke will add to that cost. No idea what the adapter is and it looks like it was installed in haste. You may have vacuum leaks as I said earlier.

Personal opinion, and probably others will agree, is to invest in a factory cast iron Q-jet manifold and Q-jet carb. The AFB is a good carb and I've run them. So if money is an issue, then at a minimum, rebuild it, remove the adapter to make sure the correct sealing gaskets have been used, add either a manual hand/pull choke or electric choke conversion. If cash flow is good, go with factory and return it back to stock.

#1406 with choke.jpg
 

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Discussion Starter #12
Money isn't a big deal, but there's plenty of other things to do on the car at the moment. Lord knows my other time sink (rock and roll guitar!) eats cash too! Haha.

Not sure if I'm going to swap back to the Q-Jet or rebuild the AFB. I don't think I have enough info yet to make that decision - but I will study up shortly.

Not sure which intake it is. I suppose I will find out when if and when I go to rebuild the carb.

Second vacuum line is the vacuum advance for the distributor.

Thanks for the help everyone - you have all been wonderful. Learning a ton.
 

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Discussion Starter #14
Yeah - as I said, I was in the process of setting the idle adjustments at the time. Had it backed all the way out and the other all the way in. They're set now.

Anyway - we're in the midst of moving, lease is up soon - so I had to get the car to the new spot. Duct taped the choke in place, and off we went... she made it the 5 miles just fine. Going to be rebuilding the carb and installing an electric choke once I can get parts (who knows with the state of affairs! I'm up in WA), but she's safe and sound.

Found out the garage is approximately 1.05 GTO's long...

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Again - huge thanks to everyone on here. I'm sure I'll come up with a bunch more "dumb kid" questions for you all soon enough!
 

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and a big azzed carport
you must be on the westside of the state like me. Im in Olympia

did you get it to idle ? about 2 1/2 turns out and warm it up

then screw 1 side in slow till the idle starts to drop and out about 1/2 turn maybe 3/4 youlle hear it smooth back
out then the other side... then do em both 1 more time.... and your golden

scott t

206 465 9165 ring anytime.... Im a 68 n 9 guy also I have 2 68 ragtops and 3 69's
[email protected]
 

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Discussion Starter #16
Yeah, the big 'arse carport is going to be great for working on it during the summer. Have 2 roommates, but even in the lease wording the garage is mine! :D

Up north actually - unincorporated Bothell.

I did get it to idle, though that was with holding the choke in place. I did back the screws down a bit. Not finally set, because I didn't really want to put my air cleaner on over duct tape. Lol!

With the duct tape in place, she fires up and idles smooth at about ~600 RPM, even on total cold start. Fun how that works.

I did squirt down the carb and gaskets with WD40 while running. No obvious vacuum leaks. Still going to rebuild the carb and add the electric choke.

I added your phone number Scott. Probably give you a call sometime soon! I've got a short list of small things to take care of before she's really ready for cruising... (brake light out, can't manage to get the darn cover off; hideaway headlights doing their stereotypical "not working at all" fun...)
 

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on the 68 lenses ... I like to use my thumbs in the upper corners and gently press and massage it
then maybe the lower .... dont pry the lense will chip and that will cost u a 100.00
sometimes a hair dryer and warm it up around the edge . the original gaskets are made from buytal
tape like the windshield original glue....fairly sure...
if the lense wont pull out try gently pushing up on the wires from behind into the socket thats not working
and see if it comes on .... we have a problem with 68's as the bulb socket holds moisture as its the lowest
point in the housing ... and the springs under the contact button IN the xocket like to rust away and not hold tight against the bulb .... thats what the gentle up pushing of the 2 wires into the rubber boot may help..

ah and the hideaway s thats a learning curve also

I just moved after 30+ years in Kirkland 11295 NE 85th above the lake
had to move from that 800.00 rental as they sold the 100 x 105' lot for 1,080,000
and built square flat roof pasty painted boxes on the whole block
I had a sweet 75x75 garden on sweet soil across the street on their other property
I miss that veggie garden,,,
 
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