Author Topic: Heavier throttle (mostly) issues  (Read 1057 times)

Offline tayto

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Re: Heavier throttle (mostly) issues
« Reply #45 on: September 14, 2019, 06:08:18 PM »
you need to completely rebuild the carb correctly. this includes installing most if not all of the parts supplied in the kit. check trouble areas leaking well plugs, worn throttle shafts, stripped threads, binding linkage etc etc. you also need to setup the carb as it came from factory, setting float height is critical. i told you how correctly hook the needle clip yet you didnt fix it and ran it anyway? did you read the mercruiser bulletin i posted? cliff's book is not a "how to" rebuild step by step it discusses theory and how to modify the carb. there will be a sheet that was sent with your kit, you can look up your carb number and it will tell you the float height. if you spend a few hours reading or searching on this forum you will find most of the answers and methods that are needed to successfully rebuild & modify these carbs. there are also a ton of youtube videos on rebuilding as well.

as far as a vacuum leak from the carb did you check to see if the airhorn or main body was warped? over torquing the mounting bolts will cause warping. also i the idle tubes are in a blind hole, i am not too sure how you were able to see the wire sticking out of the other end. i push wire in until it bottoms, mark the wire then check the other side, if they go in the same distance there is a good chance they are not plugged.
« Last Edit: September 14, 2019, 06:15:13 PM by tayto »

Offline MP81

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Re: Heavier throttle (mostly) issues
« Reply #46 on: September 15, 2019, 03:23:41 PM »
i told you how correctly hook the needle clip yet you didnt fix it and ran it anyway?

By the time you sent that, the carb was already rebuilt and on the car, so...

What sheet was sent with my rebuild kit? I did not receive any kind of sheet, aside from the link to this, which I always had up on my computer to reference: https://cliffshighperformance.com/wp-content/uploads/2018/10/1981-up-ccc.pdf

The book is pretty step by step, but I don't recall any thing related to setting float height, aside from it being just over the top of the casting surface, which it was. Was the same as the one in there before.

There are four holes right there. Two bottom out, two go through the bottom of the carb. Everything was clean.

I torqued the mounting bolts to the 12 lb-ft specified in the service manual, so those are to spec. But it definitely sounds like that's where the big leak is, as moving my hand near there "blocks" the sound.

Didn't check to see if the air horn or casting were warped, but the gasket interface seemed pretty consistent.
-1981 Camaro Z28 - 305 ci LG4 V8 - Headers, Dual Exhaust, GW U/LCAs, Hotchkis Springs/Swaybars, DD HDX Cluster
-2007 Cobalt LT - 2.2L L61 I4 - M62 SC, FE5 Suspension, Much More
-2014 Cruze Diesel - 2.0L LUZ I4 Turbodiesel - MSR Wheels, UR Rear Bar
-2017 Volt LT - Voltec Gen 2 + 1.5L I4

Offline Kenth

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Re: Heavier throttle (mostly) issues
« Reply #47 on: September 16, 2019, 12:53:14 AM »
You need to set the float correctly and hang in the inlet needle clip from behind of the float arm, no way around this.
If not, you will never get the carb working properly.
Follow the instructions for a basic rebuild in order, step by step:

https://cliffshighperformance.com/wp-content/uploads/2018/10/1981-up-ccc.pdf

https://cliffshighperformance.com/simplemachinesforum/index.php?action=dlattach;topic=4148.0;attach=1383;image

Offline MP81

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Re: Heavier throttle (mostly) issues
« Reply #48 on: September 16, 2019, 07:54:07 AM »
It looks like the clip could bind and cause the needle to stick open - but with both that, and a float that is maybe too high, wouldn't it overflow the carb with gas, and not just run slightly rich? Or can it cause rich running without overflowing the carb?

If I'm able to re-use the same gaskets and take it apart again, then I'm not opposed to doing that. Removing it from the car isn't exactly difficult, nor is getting the air horn off (the TPS plunger is a bit of a bitch, though).

That PDF doesn't really make it clear how to accurately adjust the float. Should it be 3/16" below the top of the main casting or 3/16" above the top of the main casting? The book stated the float should come above the main casting.

Is it worthwhile to get the Quadrajet float gauge to do this, or is it easy enough to do with a straightedge and calipers?
-1981 Camaro Z28 - 305 ci LG4 V8 - Headers, Dual Exhaust, GW U/LCAs, Hotchkis Springs/Swaybars, DD HDX Cluster
-2007 Cobalt LT - 2.2L L61 I4 - M62 SC, FE5 Suspension, Much More
-2014 Cruze Diesel - 2.0L LUZ I4 Turbodiesel - MSR Wheels, UR Rear Bar
-2017 Volt LT - Voltec Gen 2 + 1.5L I4

Offline Kenth

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Re: Heavier throttle (mostly) issues
« Reply #49 on: September 16, 2019, 01:19:01 PM »
A too high float setting and binding inlet needle due to misplaced clip can and WILL make the engine run rich without flooding, but flooding does occur from time to time.
A new gasket can be reused many times on the same carb.
The procedure is described on page 2 figure #3 and the fuel level settings are in adjustment data tables on pages 3, 5 and 6.
What is the application number on your Q-jet?

https://cliffshighperformance.com/wp-content/uploads/2018/10/1981-up-ccc.pdf

Offline MP81

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Re: Heavier throttle (mostly) issues
« Reply #50 on: September 16, 2019, 05:05:51 PM »
Ah, okay, that would make sense then - along with the vac leak pulling in extra air, pissing off the O2, making it dump even more fuel in - vicious cycle.

Carb number is 17081207

And cool - I figured so - it's only seen one heat cycle anyway.

I'm still puzzled why there was such a stark difference in the gasket that was on the car and the new one:


-1981 Camaro Z28 - 305 ci LG4 V8 - Headers, Dual Exhaust, GW U/LCAs, Hotchkis Springs/Swaybars, DD HDX Cluster
-2007 Cobalt LT - 2.2L L61 I4 - M62 SC, FE5 Suspension, Much More
-2014 Cruze Diesel - 2.0L LUZ I4 Turbodiesel - MSR Wheels, UR Rear Bar
-2017 Volt LT - Voltec Gen 2 + 1.5L I4

Offline tayto

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Re: Heavier throttle (mostly) issues
« Reply #51 on: September 16, 2019, 09:04:51 PM »
I already posted a picture of how to set float height, i also suggested searching on YouTube. we are trying to help you but you seem to not want listen. i am tired of repeating myself this will be my last post in this thread, good luck with your rebuild.

Offline MP81

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Re: Heavier throttle (mostly) issues
« Reply #52 on: September 17, 2019, 06:06:22 AM »
Don't want to listen, what are you talking about?

I simply asked if I need the tool to do it, or if I can use a straightedge and calipers - the image you posted shows a special tool (which Cliff said I would not need, earlier in the post). How is that "not want listen"?

I do appreciate the help in this thread, but if you feel you must go, then I can't stop you.
-1981 Camaro Z28 - 305 ci LG4 V8 - Headers, Dual Exhaust, GW U/LCAs, Hotchkis Springs/Swaybars, DD HDX Cluster
-2007 Cobalt LT - 2.2L L61 I4 - M62 SC, FE5 Suspension, Much More
-2014 Cruze Diesel - 2.0L LUZ I4 Turbodiesel - MSR Wheels, UR Rear Bar
-2017 Volt LT - Voltec Gen 2 + 1.5L I4

Offline MP81

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Re: Heavier throttle (mostly) issues
« Reply #53 on: September 21, 2019, 09:32:21 AM »
Pulled the carb back out on Wednesday and got the air horn pulled off on Thursday, then I adjusted the float to 11/32" (as specified) down from the surface of the main casting and put the needle pull clip in the correct spot.

Pull clip:


Float adjusted to the proper level - a good bit lower than it was. Oops.


The pull clip sits pretty loose there, so putting the float/needle back in after adjusting the float to check the height was always fun. Is it supposed to be that loose to the float?
-1981 Camaro Z28 - 305 ci LG4 V8 - Headers, Dual Exhaust, GW U/LCAs, Hotchkis Springs/Swaybars, DD HDX Cluster
-2007 Cobalt LT - 2.2L L61 I4 - M62 SC, FE5 Suspension, Much More
-2014 Cruze Diesel - 2.0L LUZ I4 Turbodiesel - MSR Wheels, UR Rear Bar
-2017 Volt LT - Voltec Gen 2 + 1.5L I4

Offline MP81

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Re: Heavier throttle (mostly) issues
« Reply #54 on: September 21, 2019, 09:36:21 AM »
My wife took a couple of (blurry) pics of the float measurement.

I don't have a super-wide vernier-style caliper, but I was able to go off the corner of the casting there and get pretty close to the 3/16" in from the end that it calls for.
-1981 Camaro Z28 - 305 ci LG4 V8 - Headers, Dual Exhaust, GW U/LCAs, Hotchkis Springs/Swaybars, DD HDX Cluster
-2007 Cobalt LT - 2.2L L61 I4 - M62 SC, FE5 Suspension, Much More
-2014 Cruze Diesel - 2.0L LUZ I4 Turbodiesel - MSR Wheels, UR Rear Bar
-2017 Volt LT - Voltec Gen 2 + 1.5L I4

Offline lightning boy

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Re: Heavier throttle (mostly) issues
« Reply #55 on: September 23, 2019, 01:59:30 PM »
3/16" is not the float height.
this thread was painful to read.

Offline MP81

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Re: Heavier throttle (mostly) issues
« Reply #56 on: September 24, 2019, 07:07:12 AM »
3/16" in from the toe of the float, like the measurement method calls for.

The float height is 11/32" down, which is what I said the post before (hence the 0.344" on the caliper).
-1981 Camaro Z28 - 305 ci LG4 V8 - Headers, Dual Exhaust, GW U/LCAs, Hotchkis Springs/Swaybars, DD HDX Cluster
-2007 Cobalt LT - 2.2L L61 I4 - M62 SC, FE5 Suspension, Much More
-2014 Cruze Diesel - 2.0L LUZ I4 Turbodiesel - MSR Wheels, UR Rear Bar
-2017 Volt LT - Voltec Gen 2 + 1.5L I4

Offline MP81

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Re: Heavier throttle (mostly) issues
« Reply #57 on: September 27, 2019, 05:24:14 PM »
Pulled the Idle Air Bleed Valve out to check the O-rings since, for whatever reason, I didn't the first time. Upper O-ring looked mostly fine, but the lower one was a bit...flat:



Upper O-rings - new (left) vs old (right):


Lower O-rings - new (left) vs old (right) - can see how much "flatter" the old one was:


I adjusted it 4.5 turns back from bottomed.
-1981 Camaro Z28 - 305 ci LG4 V8 - Headers, Dual Exhaust, GW U/LCAs, Hotchkis Springs/Swaybars, DD HDX Cluster
-2007 Cobalt LT - 2.2L L61 I4 - M62 SC, FE5 Suspension, Much More
-2014 Cruze Diesel - 2.0L LUZ I4 Turbodiesel - MSR Wheels, UR Rear Bar
-2017 Volt LT - Voltec Gen 2 + 1.5L I4

Offline Cliff Ruggles

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Re: Heavier throttle (mostly) issues
« Reply #58 on: September 28, 2019, 04:42:51 AM »
Even the slightest air leak past those "O" rings will make tuning impossible.  In most cases when I get into a CCC carb they are cracked, split and leaking pretty bad.  Since they route air to the idle system they will have a significant impact on idle fuel control at the mixture screws, and fuel to the off idle transfer slots which can lead to poor idle quality, and lean off idle (hesitation/stumble/bog) even if everything else in the carb and computer stuff is working correctly......Cliff

Offline MP81

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Re: Heavier throttle (mostly) issues
« Reply #59 on: September 29, 2019, 06:36:29 PM »
Good to know! I would honestly not be surprised if that lower O-ring was not sealing all that well, given it was pretty squared off.
-1981 Camaro Z28 - 305 ci LG4 V8 - Headers, Dual Exhaust, GW U/LCAs, Hotchkis Springs/Swaybars, DD HDX Cluster
-2007 Cobalt LT - 2.2L L61 I4 - M62 SC, FE5 Suspension, Much More
-2014 Cruze Diesel - 2.0L LUZ I4 Turbodiesel - MSR Wheels, UR Rear Bar
-2017 Volt LT - Voltec Gen 2 + 1.5L I4