Tell me about the QuadrajetsCarby

I got one of these on my GMC pickup and it dies every now and then for no reason other than it usually has been running hard hauling on the highway, but it has been know to do it other times as well.

I took it off and put a Holley on for now, but the quadrajet seems to make more top end HP when hauling.

Any trick or past experiences that any one cares to share.

What would you do???

Russ.

 

i have had many q-jets over the years and have all of them apart, have you had the top off yours to look inside? does it just die out when ideling after you have been hauling?

 

It is off the engine but I have not opened it yet.
I 1st thought I was starving for fuel, but turns out it seemed to be flooding the engine which caused it to stall.
Then it would not restart until it was ready.

Mostly happened when I backed off after having the throttle open when running with traffic. I am sure many members would have seen me on the side of the road in one state or another last fall.
I guess that is similar to what you are saying, but it could also stall at speed say 60mph for example.

One said to me there are some tubes or pipes inside that caused him to be stuck. I am not an engine or carby guy so I thought I ask and see what people think and what solutions they may have so I know wether I should attempt it or make another value judgement.

They are a great carby when running that is for sure.

Thanks so far, I hope my info will help in a 2nd reply.

Russ.

 

I have a box of them that I would be willing to send you just for the cost of shipping. There is a reason that they are called quadra-junk carbs. Yeah, I know there are the guys out there that will tell you that they are the best carbs ever designed, when they are running right. But when they are not, there are about 3 million moving parts in one. You do the math!

 

How much for shipping to 30011 zip code?
I'll take that box of junk off your hands.

fiftyv8,
As for the stalling problem try a thicker gasket between the carb and the intake. Also might look at the fuel line routing from the pump to the carb.
See if it runs close to any heat sources..like the lower radiator hose.
This was pretty common on the earlier GM's until they figured out the thick gasket solution.
You might also try adding a return line from the fuel filter (A/C option cars) or changing to a return style fuel pump.
What you are experiencing sounds like vapor lock.
The carb was designed to meter liquid gasoline.
When it gets hot enough, the gas goes to vapor in the bowl and the engine will quit.

BTW..I had this happen on a small block ford with a HOLLEY also.
The fuel line from the pump runs right over/next to the lower radiator hose on some of those(Like my 75 F-150).

Track town, I'm serious...let me know how much.

 

Lead well plugs in the bottom of the flat bowls may be leaking too. You can fix them with JB Weld. Truck QJs are notorious for having very rich secondary metering rods. Properly rebuilt they are good carbs, NHRA stockers run in the 10's with them. Searh quadrajet and theres lots of info on the web.

 

If Stevie G doesn't want them I'd like to get in line.
Don't know what is causing your problem. Sticky float? Plugs that mtkawboy described? Secondary rods stuck open?

 

Just keep your head in the sand if you must. If you'd like to pull out and learn the basics of how to make this carb sing, I strongly recommend the book, "How to Rebuild and Modify Rochester Quadrajet Carburetors" by author Ruggles, a CarTech publication. It's worth learning how to set up a Qjet because once you get them set up they stay working for a loooong time. Hard to make that statement with a Holley.

 

check the main stuff: power valve, acc. pump , saturated float ? , mettering rods stuck or pluged, worn parts, vacume leake?, jets. rebuild kits are cheep but so is a used holley

o ya i was told never to over tighten the airlcleaner because you can warp the top plate

 

you can do that too by tightneing the snot out of the frt mounting bolts and how much shipping to 80513?

 

Thanks guys I have a much better idea regarding these suckers now.
I will get the book and work my way thru it.
I will try some of the cosmetic stuff as well since this can sometimes be over looked, the simple stuff.

I wont be need the box of quads, one is enough for me, I do agree that when working it is a good carby for my purposes any way.

See you in the gas stations and not on the side of the highway from now on.

Thanks again all, Russ