Quadrajet rebuild

Ken47

Ken47

Active Member
Supporting Member
I bought a quadrajet carb off of kijiji this week. $20. It’s from a 1976 gm 350. I’m going to rebuild it just for fun and for something to do😄. It’s pretty clean for an old carb. Soaked it in pine sol all day today and it cleaned right up. looks almost like new. it doesn’t look like it’s ever been apart but all of the screws that hold the body together were barely tight. When I took the inlet fuel filter out I found a hard shell beetle jammed in the filter inlet. That could explain why the guy took it off. One problem I do see is there is a lot of slack between the primary throttle shaft and the housing. I’m going to put some bushings in there. An excuse to buy a new tool😄😄 I’ll post some more as I progress through this effort.
 
I'll be watching this. I have to do this same project. I already have the reamer and the bushings, but I have never done it before. I got the carb from a mechanic that said he couldn't get it to run right, but a lot of what I read says that the primary throttle shaft bushings need to be tight to avoid vacuum leaks. This carb has loose bushings.
Waiting and watching. You do it, and I'll follow suit.
 
I just ordered the reamer and bushings today. I watched a you tube video on replacing them. ( there seems to be a you tube video on everything 😄.) It looks reasonably easy. One reamer I looked at said it was self piloting (aligning) but from the picture of it I couldn’t figure out how it was self piloting. If this doesn’t work I’ll just have one more piece of shelf art😄😄
The pine sol soak worked pretty good. Took Looks of hand tooth brush work too though. 😄
 
I have been suspect of carburetor mechanics since I wore a younger man's clothes. It was nice to buy gas back then. Ray Ruff would come out to the pumps, and tell you to pop the hood while he was pumping your gas. He went for a screwdriver, and adjusted the carb, and said to try that, it sounds a little better.
He is probably the only mechanic I have ever known that didn't instantly say, "let's put a carb kit in it". Whenever I hear that, I run for the hills. Ray would fix what was wrong with your carb, and wouldn't run for the kit like it was an instant fix for everything. Trying to find a good carb doctor is harder now than ever before as far as I'm concerned.
I have 3 quadrajets now, and from what I have been reading, they are the ticket for the dual port intake I just received from Offy for my 300 six in my F100. My single barrel Carter carb ( stock) was rebuilt when I got the truck, and from what I have read as well, is that they are only good for about a year and a half or two years. It leaks down and if I don't start it at least every second day, I have to prime it to get it going again.
I got one of them from a mechanic who said he loves holleys, cause he can't make the quadrajet sing. First thing I will do is replace the sloppy primary throttle shaft bushings, as that is supposed to be the cause of a lot of vacuum problems.
I have watched a bunch of youtube videos on how to do it, and its pretty straightforward watching someone else do it. There are a LOT of videos, and they seem to me to be quite informative.
 
I agree. A lot of people think that if the motor isn’t running right the first thing to look at is the carb. My opinion is it should be the last thing to look at😄.
 
I just thought I’d throw this out here as a word of caution. I used a bucket of pine sol cut 50/50 with water to soak and degrease the carb. I though that heating up the pine sol would make it work better. I got my little induction hot plate out and heated up the solution. My garage is attached to the house and the end result was the whole house smelled (stunk) of pine trees. I guess that’s ok if you like the smell of pine trees. It was so bad my eyes were watering. Needless to say my wife was not impressed. 😄😄. The bad news is after all this carrying on I’m not even sure the hot pine sol worked any better than if it was cold 😄. Ya live and ya learn😄😄
 
Thanks for the pine sol tip. I was thinking I would have to go buy a bucket of carb cleaner. I have heard the new stuff doesn't work as good as the old stuff used to, and its expensive. If the pine sol works, I'll give that a try.
I have to say, I am really out of my element here, but I think I can do a decent rebuild with the help of all the youtube videos out there. Thanks.
 
IMO this book is the bible for Quadrajets. See if you can get a copy from the used book store or on line. There are chapters on tuning the carb for high performance engines, particularly if you use a longer duration cam which has less vacuum at idle. I've got a Q-jet on my 455 boat engine that works well.

RLIQ1fc.jpg


cIOwkpV.jpg
 
here is a before and after the pine sol treatment Sorry for the size of the image. I saved it as too large a file

es9WExn.jpg


hJbs710.jpg
 
You must log in or register to reply here.
Back
Top Bottom