wilpetty
1/2 ton status
Should I try to get another or is this one good? I don't know the model though
CK5
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I have a rochester carb...
- Thread starter wilpetty
- Start date
That is the stock carb and still the best in my opinion.
COCHEV
1/2 ton status
It will be your best option next to fuel injection
wilpetty
1/2 ton status
Thanks for the info iceman. It was really dirty so I used carb cleaner and it came out really clean. How do I check if it is functioning properly? It is on the motor out of the truck so I can pull it off...when I pulled the levers the choke barely opened but the big flap didn't open at all. My dad said the truck may have to be running for it to open the flaps. Is this true?
You can check everything before you put it on the engine and have it ready to go.
But for the big flap only opens under load on the engine.
I used to rebuild these carbs and adjust them on the bench bolt them up and they would run perfect. I also tweaked one on my 79 van and got 17mpg.
wilpetty
1/2 ton status
What would cost of me rebuilding it be? I am not sure if it is worth it right now. I don't believe it leaks and I probably will just need to adjust it once I get the truck running and it will be fine. As far as performance goes, I won't get my bang for the buck of buying something else I suppose correct? I am looking to have quite a bit more power than the bad 350
Kaiser85
1/2 ton status
The q jet carbs are good all-around carbs. The ones that came OEM 81 and later had all the emissions stuff. The more vacuum hoses youve got, the more chances for a vacuum laek youve got. Alot of people stray from the q jet carbs for a very simple reason.... theyre pretty complex carbs. The linkage for the choke (big flap) is very easy to get wrong. You shpuld be able to mainpulate that by hand even with the engine off BTW.
Alot of guys like holley for performance. Alot of.guys like quadrajets for the economy/performance. Others like edelbrocks for simplicity, reliability, and the aforementioned. Every carb has something unique to offer, that the next one doesnt. Its usually nothing more than a matter of opinion. And im sure you know that in this subculture, a mans opinion is undeniable fact in his world. Lol.
Ill say this from my experience so far. The post 80 oem quadrajets were meant to run a certain way with a certain number of goodies running off the vacuum. Removing this stuff CAN be done, but it takes a pretty stout knowlege of the workibgs of that stuff. Start aimlessly removing that emissions stuff, and pretty soon youll be running like poo.
PS..... if the big flap will only move a small amount, the linkage inside of the carb is messed up. Like i said before, you should be able to manipulate that choke flap by hand regardless of.engine running.or not. This same thing is going on with my blazer.... which is the reason ive got a new edelbrock 1405 on tye way to my door
Alot of guys like holley for performance. Alot of.guys like quadrajets for the economy/performance. Others like edelbrocks for simplicity, reliability, and the aforementioned. Every carb has something unique to offer, that the next one doesnt. Its usually nothing more than a matter of opinion. And im sure you know that in this subculture, a mans opinion is undeniable fact in his world. Lol.
Ill say this from my experience so far. The post 80 oem quadrajets were meant to run a certain way with a certain number of goodies running off the vacuum. Removing this stuff CAN be done, but it takes a pretty stout knowlege of the workibgs of that stuff. Start aimlessly removing that emissions stuff, and pretty soon youll be running like poo.
PS..... if the big flap will only move a small amount, the linkage inside of the carb is messed up. Like i said before, you should be able to manipulate that choke flap by hand regardless of.engine running.or not. This same thing is going on with my blazer.... which is the reason ive got a new edelbrock 1405 on tye way to my door
I am not sure what year you carb is but here is a link to the manual for whats on my K5.
http://www.whateveristrue.com/chevy/Rochester-Quadrajet-4MV-4MC.pdf
The Smaller front choke doors are the only ones that will operate by moving the linkage. The large rear Choke flappers are pulled in by suction in the intake when the motor is under load.
You should however be able to open them with your fingers when the motor is not running and spray cleaner in there.
Spray it down with carb cleaner. make sure to get in all the passages and make sure everything that moves is free and nothing is sticky.
Then give it the base setup from the manual for fast idle. That should get you running as long as nobody tinkered too much with it before.
http://www.whateveristrue.com/chevy/Rochester-Quadrajet-4MV-4MC.pdf
The Smaller front choke doors are the only ones that will operate by moving the linkage. The large rear Choke flappers are pulled in by suction in the intake when the motor is under load.
You should however be able to open them with your fingers when the motor is not running and spray cleaner in there.
Spray it down with carb cleaner. make sure to get in all the passages and make sure everything that moves is free and nothing is sticky.
Then give it the base setup from the manual for fast idle. That should get you running as long as nobody tinkered too much with it before.
wilpetty
1/2 ton status
Thank you! I cleaned it and I'll see how it does on the new motor
COCHEV
1/2 ton status
If you haven't already, its worth getting the rebuild kit from Napa. That way you get a new accel pump and float jet and seat and all new gaskets. You will also be able to check float height and /or replace the float as well.
yeah the kit is cheap and has all the needed adjustments.
wilpetty
1/2 ton status
How difficult and long is rebuilding a carb?
It's not too bad. read this and it will give you a general idea.
http://www.vetteprojects.com/kstyer/quadrajet.htm
I just did mine this past week, the kit and the float was around 56 bucks at napa.
Also, take lots of pictures is you are not familiar with how things come apart.
put it on and run it..
wilpetty
1/2 ton status
Will do
Old motor coming out tomorrow and in with the new hopefully in a couple more days. I hope I am cruising around town in it by the weekend 
