Tips and advice for first Quadrajet rebuild

[NGH14]

First time posting here after lurking for quite a long time, but I decided this weekend I'm going to go ahead and rebuild the quadrajet off of my 86' k2500 camper special after it not being touched for 30 years. I've done quite a bit of research before diving into this thing, as I'll be following along to this video: https://youtu.be/oLpUqS9zrP8?list=FLsWeNhytPEdcxWoQxhvZY7Q. I'll also be referencing a few rebuild books one of my college teachers had given me. Already noted to not pull the power piston out as well haha.

A few questions I have regarding it, I did order a complete rebuild kit from NAPA, and I also had ordered a new accelerator pump, float if needed, and secondary pull off if needed. I was just wondering if there's any tips or tricks I should be looking out for while I'm disassembling that perhaps the person in the video did not cover, I know there seems to be a debate about sealing the plugs with JB Weld or epoxy, and I was thinking the JB Weld route would work best. My choke is also riveted onto the carb, and I was wondering if 10x24 3/8 self tapping screws would work for the rivet replacements?

I was also wondering what would be the best method tuning wise to go for after initial start up after the rebuild.

Thanks in advance.

 

[Jarhead79]

Talk to Quadrajet Power here on the forums, he builds theses a carbs and has a great rep for building for your engine size etc. Unless you just have it in your head you want to do it yourself, that's cool but if you have doubts, talk to him!

 

[throttle out]

So your choke pull off is riveted?? The couple I've been through, both of them slid on to the carb body. In any case, I would recommend putting some calipers on the rivet that comes out of the hole and taping the appropriate thread pattern into it. Be sure to buy a bottoming tap! As far as the leaking plugs issue goes, did your tuck have restarting issues once it was up to temp? If not, then I would not trouble yourself with blobbing jb weld on the plugs. Once you have it apart it should be evident if a fuel leak is occurring at those plugs. It's my understanding that Rochester fixed the issue at some point and I would think being your truck is an 86 and the last year for a carb, you are probably in good shape. These carbs are VERY sensitive to float height adjustment. If you are replacing the float, be certain your measurements are spot on the recommended float height spec for your application.
I got all of my parts from here - http://www.cliffshighperformance.com/
I bought the book cliff wrote and it was very helpful. we can reference it if need be, just let me know
I recently did my father's Quadrajet on his 70 Vette and was pretty impressed with it. I've always heard nothing but bad about these carbs (quadrajunk) and so on. They have quite a bit of adjust ability compared to other brands and I think that is where people get in trouble with them.

Good luck man!!

 

[NGH14]

@Jarhead79 I am planning on doing it myself. If I can tear a part an Allison transmission I think I can do this with as much research as I've done haha. But considering this is my first time I definitely want as much advice and and knowledge as possible.
@throttle out My choke/thermostat assembly is the part that's actually riveted onto the carb. I figured once I have them out I could run to ACE and get the proper size. I just figured those sizes would work properly. My truck hasn't had any issues restarting, just having a hard time running smooth until she warms up, along with it not kicking out of high idle right away. Hopefully shouldn't have to replace the float, just got one in case.

 

[Quadrajet Power]

There are several things you should do in my opinion. First of all, beware of kits from stores. Many don't have quality parts to use and may fail with current fuels. Especially the accelerator pump.
Always replace float.
You can drill out the rivets on choke and use self tappers to reattach.
Take pictures as you pull apart so you kno where parts go.

Clean it good, and clean out idle tubes.

Kit doesn't provide these critical items for well built Quadrajet.
Float
Complete accelerator pump assembly
Jets ( needed to calibrate for today's fuel)
Primary shaft bushings
Secondary air valve cam and tension spring ( most are cracked and all are worn)
Fuel filter
Internal springs. They are old.

Have fun with it! If you run across anything you need help with let me know.

 

[NGH14]

Well things seemed well for about a day after the rebuild haha. Completely tore it down, cleaned the insides as well as I possibly could without damaging any of the coating inside the case, rebuilt it with a NAPA kit, with a new float, and accerlator pump from quadrajetparts.com, and a new secondary pull off. Didn't JB Weld the plugs when I put it back together since it looked like the plugs were not leaking.

Ended up getting everything back together, put it on the truck and it fired right up after a fuel pumps. Noticed it was having issues kicking down from high idle, which was the same problem I had before the rebuild. Truck ran incredibly better without any back firing issues. Ended up driving to work today, let it sit for around eight hours, went to go start my truck, and it wouldn't stay running after initial firing up. I would crank and pump the pedal four or five times, truck fires for about three or four seconds, then shuts off regardless of me pushing on the pedal or not.

So I'm going to pull this thing back off in the morning and see what's going on. I think I might have possibly put the choke linkage back together incorrectly, since the lockout cam is freely moving. If anyone would have any other suggestions at what to look at, I'd greatly appreciate it.

 

[SkinnyG]

It will be a balance between fast idle speed setting, and choke spring tension. It will take a bit of time of fiddling every couple of days.

If the fast idle is too slow, turn it up a bit.

If it is running pig rich, or takes a l-o-n-g time to release the choke and/or come off fast idle, loosen the choke.

If it comes off fast idle too quickly and/or stalls, add more choke.

I have mine set so the choke comes off as quickly as it can without idling too slowly or stalling.

 

[Quadrajet Power]

Email me and I will send you my tuning sheet with pictures. Maybe it will help.

I would take off the secondary lock out piece.

[email protected]

What is your float set at?

 

[NGH14]

@SkinnyG My fast idle seems to take quite a long time to kick down, as far as loosening the choke goes, are you talking about the choke itself or the speed adjustment?
@Quadrajet Power Is it even necessary to have the lockout piece on the carb? I set my float to 13/32" as per the data table I had included with my rebuild kit, which was for a 17085003 quadrajet.

Thank you guys for the quick responses.

 

[SkinnyG]

Loosening the choke is loosening the spring tension holding it closed.

 

[Quadrajet Power]

The lockout blocks the secondary from opening when the choke is engaged at any level. I remove them unless my customer specifically request it.

I emailed you my tuning sheet this morning.

 

[SkinnyG]

In the bad old days the choke would lock out the secondaries to avoid a lean condition, a stumble, and sometimes a pop through the carb, when going to wide open throttle while the choke is on.

Grandma didn't care for that while sipping her martini and listening to Perry Como, so carbs got that. It's not vital to keep - many people disable it.

 

[NGH14]

Thanks for the tips and advice guys, definitely helped reading that tuning sheet, I'll have time in the morning to partially disassemble this thing again and see what might be wrong or what has gone wrong. Can't imagine too much had happened considering this thing was running fine for over a 24 hour period and all of sudden started to have issues running. Thinking it possibly might be leaking the fuel out of the bowl so quickly it's causing no gas to stay in the bowl long enough to stay running. That's just what I had observed when this issue occurred. Unless I have something plugged between where the fuel line and carb connects, which is something I'll also take a look at.

 

[74 Shortbed]

Use a good quality filter also..

 

[1987 GMC Jimmy]

I have a question that's not directly related to your current dilemma, but I do want you to cover all the bases. My Quadrajet was untouched for thirty years (250K miles), and the primary shaft was total slop. I had it bushed because if you leave it that way, it results in a vacuum leak that'll contribute to a higher idle. I had it done on my Rochester TBI also, and it had 183K miles.