BillK

Hey guys. There have been a lot of threads about Q-jets that seem to require a ton of cranking after sitting for more than a few days. There are the well known issues of the well plugs and it seems like a lot of people want to blame the ethanol in the fuel. Anyway here is my story. My Wifes Riviera had been getting harder to start when sitting for some time. A year or so ago the plastic timing gear gave up in the 307 after 220K miles so I pulled the engine and trans and went through them both. I went through the Q-jet at the same time. I have probably done a hundred Q-jets over the last 40 years or so so I am pretty good with them. Anyway got it all back together. Car runs like new money but darn if it wasnt still hard to start after sitting just a few days. Had to crank for 40 seconds or so.

I went searching and actually found a low mileage Q-jet on Ebay that was the identical part number as hers. Got it here, took it apart and cleaned it in my ultrasonic cleaner, put it back together with a new float. This was back in December. Well that fixed it. It can sit for a week now and two pumps on the gas and she starts right up every time.

I have looked and looked at the original carb and just cannot find anything wrong with it, at least not that I can see. Dont have a clue what the problem was but it is fixed

Just thought I would post an update. I never really thought it had anything to do with the fuel because my S-10 can sit for weeks at a time and it starts right up with a couple of pumps to set the choke.

oldcutlass

Have you tried setting over some paper towels with the bowl full and see if they get wet over time?

BillK

Yup. I had the center section sitting on the bench at my shop for a week filled with gas and it didn't lose a drop. This is the first qjet that has ever done this for me. I always seal the bowl plugs when I do them. It's got to be something strange.
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Anyway the replacement carb took care of it.
Just would love to figure out what the problem was but I have better things to do 😃

shiftbyear

Bill, I don't know what the problem is, but I was wondering if you install the needle to float clip on the carbs you rebuild. Maybe leaving it off keeps the needle on the seat and requires longer time to replenish the bowl during startup. Just a theory, you definitely have a head scratcher. Glad you solved the problem though.

BillK

Yup, And I also know how it is supposed to go It is an E4MC and I have the factory tools for adjusting the electronics etc. I have never had a problem in the past. I don't know what the deal is with this q-jet but at this point I am not wasting any more time on it. It will probably go in the scrap metal bin

Olds64

That's good that you fixed the problem. I always seal the bottom of the fuel bowl too when I rebuild a Qjet.

You might consider keeping that old carburetor for parts. Qjets are limited in supply. Even 20 years ago when I frequented the salvage yards they were always the first parts to go.

Greg Rogers

Don't throw it away, you may regret it. Yeah as you said this comes up a lot. My Cutlass does it and my Vista used to do it (Sold it). Someone said one time that the fuel filter can come with a little flapper type one way valve and I have seen the fuel filters with and without it, but that doesn't seem to be a factor because how could the fuel go back up thru air into the float and back down thru the fuel pump?? Unlikely! Can the gas evaporate cuz of the heat of the shut down engine? This topic was just discussed in "Ask Ray" in one of the Hemmings magazines.

76olds

My q-jet went into the scrap bin years ago as well, after a rebuild not lasting for the season. Kinda wish I had of kept it now. Not that its a great loss. However, now that I'm a little older I would have liked to tinker with it to see if they do in fact perform better then the Edelbrock's as some say they do when tuned and running flawlessly. I wouldn't know the difference now, can't be bothered to find one and try it again. If ther was a difference in performance, my butt didn't feel it that spring. I been running Edelbrock's ever since. For as many good reviews Edelbrock's have, they have some bad. I haven't experienced a bad one yet.

Eric

olds 307 and 403

Your factory Qjet was set very lean from the factory and a good quality kit helps them last. Consider yourself very lucky on the Edelbrock, hot start issues go back to the 60's with the AFB/AVS. Also the casting quality is not good compared to the original Carter castings and a few have spent hours tuning to no avail. I have experienced a few Qjets that no rebuild could fix them. I have had strange choke issues, bending linkage this year but it now fixed I believe.

Inline

.. And this is how all the rumours start.. One guy telling casting is poor compared to 70's and now they are utter crap. I could say same about nowadays Weber DCOE's - castings are crap compared to older ones ( surprise surprise, Weber casts Edelbrocks too, Edelbrock aint casting them.. ). Id also bet that the new vs old casting as is, wont differ hp wise that much anyways.. You can add phenolic etc spacer under the carb always.
And theres also whole internet full of posts about not getting Holley tuned too. Most bad talk about Edelbrocks imo relates for bog when going to secondaries. And this goes to AFB model directly, since they have pre-set blade angle and weights on their air-valve over secondary butterflies, which should open secondary side when theres need for it via vacuum. Problem on these is, that the blade-angle and weight is perfect for just ONE situation. Carter made maybe hundreds different blade-angles and weights for those, Thats Edelbrocks shame, but it wont make the design still utterly crap.
Theres always the AVS models with adjustable airdoor. Sure, its whole other world when you go to higher-end holley style carbs where you can adjust everything from idle-air bleed to whatever, but for street, these are fine. Whos missing the 5hp from flywheel?
Personally, im really excited to test the new AVS2 carbs.

Ps. Nothing personal Olds 307 and 403

olds 307 and 403

Nothing personal either, nearly every poor running car complaint on here had an Edelbrock carb, enough to keep me away from them. It is obviously still a work in progress. I personally like the Qjet or Street Demon for a street carb, it will be my next one.

BillK

I bet there is 2000 of them on E-bay right now Not much demand except for guys like me wanting to keep a particular car as original as possible.
https://www.ebay.com/sch/i.html?_fro...retor&_sacat=0

Mine is in pieces. I might stick a few of the parts in my parts bin but the rest of it is in the scrap metal bin.

76olds

I'm happy to be one of the lucky ones haha. I added a 1" 4 hole phenolic spacer, so I don't have any issues with heat soak, fuel percolation or hot starts that many experience. I can fire mine up and go, the only time I had some hesitation and stumbling idle was with a vacuum leak, the spacer took care of the harder hot starts. I really think they are a great carb for a mild build, easy to install and quick to tune, essentially trouble free for a street cruiser. I can't comment on what they would be like on a strip car or a hot street build thou.
That's been my experience with them for over 10 years now.

My 455 build will be going EFI, so no need to mess with setting up carbs for this build.
shhhhh my wife doesn't know about it yet haha. I have a nice 442 covered up at the shop that she thinks is being stored for a friend. I have to build a few small angle bracket, U bracket and dog leg brackets with pierced holes and a few small electrical panel dies for automated machine electrical boxes on the side to keep this going ahead haha.

Destructor

My Eddlebrock works beautiful. I've had it close to 20 years. No bogging at all. I had it apart once for a clogged jet. I do have the no start issue if it sits for 40 minutes or more when hot but its only a nuisance. For me the switch from two barrels to 4 was easiest with the Eddle. That being said I wish I had an original Q jet. My past cars had them and they always worked well and stayed in tune.

76olds

I had the hard to start issue when driving a few hours then needing to stop for gas. No problem with hot starts after adding the 1" spacer. I also took the weather stripping off on top of the firewall to get the cool air to flow through the top of the engine bay better. Redneck ram-air .

Eric