On the way home from the Washington GTG, just after putting 40.2 gallons in the rear(holds 40) and 20 gallons in the front, the thing sort of died going up the first hill. It didn't quit, just wouldn't go. We made it to the next exit and replaced all filters including the one in the Q-Jet to no avail. A road service guy took the top of the carb and found some trash in it, put it back together and it ran but not well. We made it home but had to keep the revs high to make it up even slight hills. Question is, do I have the Q-Jet rebuilt, buy a new Q-Jet, or buy something else. My son-in-law says that the intake manifold will only take a Q-Jet and we would have to get a new intake manifold if we want to get a different type of carb. Would appreciate comments from those who "been there, done that".
Jim

The fella who worked on our MH was great. He was with us for 6 hrs including travel time & a trip to the store. He bought 3 filters for us & took the carb apart with me holding the flashlight which took at least an hour or more. He was a diesel guy but knew enough to take the top off carb which is in my opinion very complicated without having a workbench. I learned that I don't won't ever be doing that Only chgd us $200.
I guess we were the third of "everything happens in threes". My pics are minor compared to Nicks & Marys but I took them anyway.


OK it's not as dramatic as Mary & Nick

Jim calling for help.

three of the fuel filters/the mechanic only found two new ones & used the best of the three on the return line. We are all puzzled about a filter on the return line. & he replaced the one up in the carb.
IMG]http://i687.photobucket.com/albums/vv240/barth_upload/pictures/P1010066.jpg[/IMG]
Mr Wyatt assessing our delimma

If you are in the Staunton, VA area he was great

Our welcoming committee Luke, Julie & Jeremy Red, Beau & Joe

Tere

The Q'Jet is a constant problem that never gets better. A new Holley will solve the problems and there are a number of adapter plates available to mate to just about any intake. Call Jegs or Summit and they can give you the necessary adapters for the GM intake to fit. If you have changed the cam or any change in displacement (boring the block, stroking etc.) be sure and tell them. They can get you going very quickly.

I would have thought Holley, but a quick Google of "Holley versus Quadrajet" provided a surprise. Almost everyone leaned towards the Q-Jet for durability, drive-ability and dependability. Who knew?

Jegs sells re manufactured Q-Jets for $299 and I'm sure there are others.

I would recommend you pull your spark plus and read them for tell-tale signs of what is wrong. Could you have gotten bad fuel? Could you have a collapsing fuel line under load? Plugged vent in the fuel system or gas cap?

Additionally, if you aren't running an HEI ignition, that would be a huge benefit to reliability.

With gas engines it always boils down to spark, fuel and timing!! I always try to eliminate two, which points towards the offender.

Corey

Is it possible the second line with the filter was to your generator and not a return line? I've never seen a return line on a Q Jet before. Very fishy!!

Corey

quote:

Originally posted by Jim and Tere:
On the way home from the Washington GTG, just after putting 40.2 gallons in the rear(holds 40) and 20 gallons in the front, the thing sort of died going up the first hill. It didn't quit, just wouldn't go. We made it to the next exit and replaced all filters including the one in the Q-Jet to no avail. A road service guy took the top of the carb and found some trash in it, put it back together and it ran but not well. We made it home but had to keep the revs high to make it up even slight hills. Question is, do I have the Q-Jet rebuilt, buy a new Q-Jet, or buy something else. My son-in-law says that the intake manifold will only take a Q-Jet and we would have to get a new intake manifold if we want to get a different type of carb. Would appreciate comments from those who "been there, done that".
Jim

I like (and use) Holleys on hot rods and hot boats. I prefer Qjets on motor homes and mild street vehicles because of their better part-throttle operation, economy and fire resistance. The Holley has narrow gaskets between the main body and the jet blocks and the float bowls. An RV that gets hot, then sits for a winter, can end up with dried out, shrunken gaskets that leak fuel on top of the intake manifold. You can find a little more on this by searching the site for Holley.

I believe Lee posted a good Qjet guy.

I had mine done by C&J Engineering in Whittier, but they are a little high for a stock application. I needed some real expertise because of my engine, and I have been happy with their work in the past.

An Edelbrock Performer is not a bad carb. Essentially a modded Carter AFB, which was a good carb, but lacked the small primaries which make me like the Qjet.

If you do go Holley, I would recommend a 3310. I keep one around as a trouble-shooting substitute, and it works well on everything, literally from a 3 liter Corvair to a coupla 502 Chevies.

I'd stick with the Q-jet. After doing extensive research on them over the last couple weeks I determined that it is important to understand the Q-jet or find a mechanic that does but that the negative reputation is apparently undeserved.

Were you keeping revs up or keeping the foot in it? Revs up would point to transmission, foot in it would lead me to think about carb icing. Carb icing would give the problems and after sitting the chamber thaws and might not get quite so choked after the time frame. Humidity might have dropped significantly after the 6 plus hours. Did you remove or change the position of the heater/plenum hose to the carb?
I prefer the Q-jet and AFB but it might be easier to buy a new Holley than find someone capable of doing the rebuild reliably.

From a 2005 post - He's still there.......
- - - - - - - - - - - - - -

For those who may be contemplating having their 454 Q-J carb rebuilt and don't have a local reliable source, I'd highly recommend that you pack it off to: Auto Clinic, 722 M-139, Benton Harbor, MI 49022.

Oscar Heritz, the owner, has been rebuilding carbs full time since high school - he's a year or two from retirement now. He specializes in GM products. He's inventoried "cleaning products" that the EPA yanked off the market years ago, and your carb comes back looking better than the day it was originally manufactured.

I think I spent less than $20 shipping both ways....More than off-set by his small town labor rates......

He'll gladly answer any phone questions: call 269-927-2237 (If he sounds a tad grumpy, it's because he is, but it grows on you .........)

You have to be a tad grumpy working on Q-Jets! My take on them...when they work properly, they are great. It's just getting them to work properly. The other thing is that most every average repair mechanic can and has worked on a Holley. Parts are readily available. And yes, they do make a Holley that will bolt on in place of a Q-Jet with no modifications to the intake. The Edelbrock will also bolt on in place of a Q-Jet, though I am not a fan of that carb either. But I am not familiar with MH applications that bill h speaks of previously.
And by the way, it does sound like a carb problem which would mean rebuild or replace.

quote:

Originally posted by Bruce & Kathleen:
You have to be a tad grumpy working on Q-Jets!

LOL. Sounds like you have met my carb guys. Or at least the grumpy one.

That said, getting the last bit of perfection out of a Qjet requires infinite patience and a source of needles and springs. And either a flow bench or a dragstrip.

quote:

they do make a Holley that will bolt on in place of a Q-Jet with no modifications to the intake.

I don't think they have made it for a while. The one I used was a 6619. It was a good performing Qjet replacement, but didn't get the mileage that the Qjet did. In general, Holleys don't offer the precision fuel mixture control that the constantly varying tapered needles of the Qjet.

Holley still makes a 600 & 650cfm spread bore carb. Not saying it is better than a q-jet, just an alternative. Again, if the q-jet is tuned properly, it is a great carb. But that is alot easier said than done. Just about every mechanic can work on a Holley.....

I'm wondering if there's a sock filter in the fuel tank. Frankly, the issues, to me, don't all point to a carb problem. Q-Jets may deteriorate over time, but I've never had one just quit.

The symptom is also one of a failing fuel pump.

In short, I suspect inadequate fuel supply.

quote:

Originally posted by Rusty:
I'm wondering if there's a sock filter in the fuel tank.

The symptom is also one of a failing fuel pump.

In short, I suspect inadequate fuel supply.

Either way, a fuel gauge would be useful.

Another possibility is an old and cracked rubber fuel line sucking air. As a temporary measure only, you can run some copper line up in to the cockpit, with a few inches of clear vinyl tubing. Any bubbles will tell you.

If You find you have good fuel presure and Qjet was running good before this, I would find a good Qjet rebuilder rather than change carb. Qjet have in my opinion have very good metering system. Find a GOOD rebuilder even if you have to send it out. In my youth days I rebult several Qjets, Now days good carb cleaner to expensive,stinks and not as good as pre EPA days. Let a good pro do it. A rebuilt Qjet, new plugs/wires and no vacume leaks can sure make an engine purrr.
Doorman
Doorman.

quote:

Originally posted by Rusty:
I'm wondering if there's a sock filter in the fuel tank.

There probably is. GM used them, and Barth might have left it in.

I had a sock clog on a car, and used tubing stuck into the filler neck for trouble shooting. I wanted to know for sure before dropping the tank.

My own situation was perverse....I had acquired a floating gob of slime that wrapped itself around the sock whenever I went uphill with a low tank or the tank got really low on flat terrain. Adding gas made it run OK.