65-442

The title said it all .... I have a 66 or 67 425 with a Q-jet carb on it and it either needs rebuilt or replaced. What do you think ........ Can I buy a rebuild kit and do it myself, should I send it out and have it rebuilt, should I buy a new Q-jet, or should I throw it out and buy a totally different carb.
Thanks for the input.
Gary

Olds64

If you are rebuilding your car to be "original" I suggest rebuilding the carburetor. Q-jets are decent carburetors but it takes a skilled hand to rebuild them properly. You could always try to put a kit in it. It wouldn't hurt anything, plus if it still doesn't run to your statisfaction you could send it someplace to get rebuilt professionally.

MX442

I bought the book and studied a few carbs. I rebuilt it myself, and am very happy with the results! With a little wheeling and dealing, I picked up a few cores, sold one, scrounged for parts, bought a rebuild kit and a pulloff. Total investment = $60. As far as skilled hand... If you follow the instructions, it is relatively easy.

Olds64

I've rebuilt multiple Q-jets and I've never been as happy with them as a new carburetor (ie. Edelbrock or Holley).

That being said I'm having Danny Sarvis rebuild my Q-jet. He is a member here (70Wcars). He lives in TX and has decent prices for his rebuild services.

Oldsmaniac

What is your carb doing? If you are unhappy with the Rochester you could try a Holley.

svnt442

He's having issues now. Just throwing a Holley or Edelbrock won't make him any happier. Both would require tuning to make the run correctly.

I suggest that with no experience with rebuilding carbs to have a pro do the rebuild on this one. If he wants to try his hand at it he can get a core carb and try it himself so he doesn't mess this one up.

My $.02

Jamesbo

X2 Throwing money and/or parts at a problem is not a wise choice.

citcapp

What he said

65-442

I've rebuilt quite a few carbs in my day just not a Q-Jet. The problem I have with it now is that it does not idle smoothly and when I start from a dead stop and put the gas on slowly it hesitates for a moment. It never stalls or quits running. Where does everyone suggest I get the rebuild kit from?

Oldsmaniac

Since I asked the question, and got a response, I can suggest a few things. Hesitation when accelerating from a stop is often due to a worn accelerator pump. An erratic idle can be caused by vacuum leaks , idle mixture screws not adjusted properly, or a number of other things such as improper float level, etc. If you have rebuilt carbs before you should have no trouble with the quad. Get the carb number off the carb and go to NAPA and they will get you a kit. It is important to blow all passages with compressed air when its apart and check for leaking casting plugs that the Qjet is prone to..

2blu442

I've seen a few books describing how to go through Quadrajets but have never looked one over. Anybody have a good reference they like and could recommend to 65-442?

Coltonis

BAH, When I rebuilt my quadra-jet I had never seen a carburetor before in my life... Mine ran. My engine was NUKED even and it ran.

Rebuild it!

If you get a kit from NAPA, it probably won't come with a float.(Mine didn't at least.) NAPA does sell them just have to buy it extra. They are cheap so I would say just replace it and realign it. Then you know that won't be a problem anymore.

My first thought, was the Accelerator Pump as Oldsmaniac already mentioned. (Parts for that should come in the NAPA kit.)

This is the book i used for reference.
http://www.amazon.com/Rochester-Carb.../dp/0895863014

Might even be available at your local Borders Books or Barnes&Noble store.

It has everything you will ever need to know about quadrajets in there. (Or carburetors in general for that matter.) Also covers how to seal the well plugs. LOTS of pictures, diagrams, charts, etc.

Some of the 'Performance Tips' are kinda debunked now (i.e. the claim that the stock fuel filter cartridge restricts flow), but stick to the standard stuff and your golden!

Some quality Googling can give you enough info to get the job done too, but I got the book mostly for the diagrams.

Also, http://www.carburetion.com/ is a good source for some of the odd parts that stores can't always get.
(Choke coils, vaccum diaphragms, filters)

The hardest part of rebuilding the carb for me, was finding the frickin' carb-dip cleaner chemical!

78cutlass

I recommend tasking Sparky's Carb Svc with rebuilding your carb. Trust me, you'll be estatic (jumping up & down with joy) once you get the carb back from Sparky's. Greg/Bill, of Sparky's are Q-jet gurus. They'll make that thing work like a fine tuned violin.

70 cutlass s

Sounds like the float level needs to be adjusted don't give up give it a one more chance bet you get it.

Oldsguy

Don't forget to eliminate the possibility of a vacuum leak first. You carb may still need to be rebuilt but a poor idle and off idle acceleration could easily be caused by poor vacuum.

65-442

lots of good info, thanks. I'll play with it awhile and see what happens, got all winter to worry about it. It runs "OK" now but I've never been one who likes just "OK" I want it to run great. I'll look at all the suggestions and go from there.. Thanks. Gary

easytobedead

do you guys use dips or cans to clean the crabs?I want to get it as clean as I can! an the cans dont seem to give me what i want.

Destructor

Rebuilding is fun, I rebuilt 3 Q jets with excellent success, don't disturb any settings like rods. Even your idle screws may still be good. Count the turns when you remove them. Replace the float. There are plugs which may leak and throttle shafts may be worn. Also some brass tubes may have dropped out and will need to be tapped back into the top piece of the carb. Rebuilding is mostly cleaning and replacing gaskets and float.

OLD SKL 69

What are you trying to clean off?

Others have given good advice already. Do you have a vacuum gauge? If so, check for a good steady reading. If it is erratic, you probably have a vacuum leak. Could be as simple as a vacuum line or a base carb gasket. Carburetors get blamed for lots of issues but I check the ignition system first to rule out any problems there. If your timing and ignition system is fine, then buy a carb kit.

A carb kit will contain all the gaskets, accelerator pump, and a needle and seat assembly. You can buy a float from NAPA, just bring yours to match it up as there are two different ones. '

Put all the new parts in, use the reference chart for adjustments. Start with the fuel adjustments screws out 4 turns from completely in. After fine tuning it, if you still have a slight hesitation off idle, then it will require another test.

When the car is running, grab the accelerator linkage and raise it up to around 1200rpm's. This will eliminate the idle circuit. Close the choke valve about halfway. If the idle goes up, it needs more fuel and you will need to play with the jets and/or metering rods. If it tries to stall, then it has the right combination.

I have done this many times with excellent results. Let us know what you find out.

easytobedead

Years of grease,oil,dirt and what ever else got to it,Just want to clean it,make it look as good as it should.