Choosing a replacement carburetor

[airdale94]

Your float is probably shot that's why it's over filling. If it's brass it might have a hole or split seem. Did you adjust the float level when you rebuilt the carb.?

[70cst]

I had this company rebuild my carb. It came back like a brand new carb. Its my understanding they sell rebuilt carbs also...


ReCarbCo
http://www.recarbco.com/

Oh yes Ride The Snake...

to the forms and from Ohio

[Ride The Snake!]

Originally Posted by airdale94

Your float is probably shot that's why it's over filling. If it's brass it might have a hole or split seem. Did you adjust the float level when you rebuilt the carb.?

Yes, I stated that in my last long post, but I understand you might not have wanted to read all that. I think it was originally at 26/32" and I lowered it to what was spec according to the kit (23/32"). I forget what the float drop was, but I adjusted that to spec as well. The type of float is the brass type. I suppose that if it did have a split in the seam and sunk to the bottom, that would cause the bowl to overfill. I'll examine it tomorrow when I go to town on this carb one...last...time. If this fails, it's replacement or professional rebuild time.

Even if the float is bad and the bowl is overfilled, shouldn't the truck still start?

[Ride The Snake!]

Haha, thank you for the welcoming. Ohio, huh? I'm from Berkeley, CA. Yes, even someone from super-liberal Berzerkeley can appreciate a gas-guzzling classic American V8.

[geezer#99]

No it won't start if the bowls overfilled!
It's flooded then.

[GMCJOE]

Found these 2 carbs on here. The one on the left looks like it would run as is, but I usually rebuild all used carbs I get. If your are going to do a rebuild, just do it on the one you have.

http://67-72chevytrucks.com/vboard/s...d.php?t=541853

[airdale94]

It should have attempted to start initially but yes once it floods no. Try holding the pedal to the floor while cranking to keep the throttle plates open and try to clear out some of the gas. If it attempts to fire but chokes out I'd say it's definately your float.

[LEEVON]

Regarding the harness, it depends on what your goals are. There are alot of simple aftermarket harnesses that would do the trick but if you want plug and play just be patient with the classifieds until you find one. Engine harnesses are usually not found in good shape, so a new replacement/stock version would do the trick and they're not crazy expensive. For the dash harness, lots of nice originals pop up. I just put a used one in my nice driver quality truck and couldn't be happier. Plug and play.

[mrsmothers]

A Q jet could be the worst carb ever made. Thats one of the first things I throw out I have a holly double pumper on my 71 its a pretty good carb really easy to tune and rebuild.

[Ride The Snake!]

Originally Posted by mrsmothers

A Q jet could be the worst carb ever made. Thats one of the first things I throw out I have a holly double pumper on my 71 its a pretty good carb really easy to tune and rebuild.

Not that I really know in this case from experience, but a lot of people who work on these vehicles would disagree with you and say that if tuned properly, the combination of fuel economy from the primaries and oomph of the secondaries in a Q-jet are unmatched for a stock motor. Also, I've read numerous times that a double pumper on a stock motor is a bad match.

I tend to be one of those people who believes stock things are engineered the way they are for a reason. Aftermarket doesn't always mean better.

[Ride The Snake!]

Originally Posted by airdale94

It should have attempted to start initially but yes once it floods no. Try holding the pedal to the floor while cranking to keep the throttle plates open and try to clear out some of the gas. If it attempts to fire but chokes out I'd say it's definately your float.

Took it apart again today, made some slight adjustments to float height and float drop. Got it to start once, it ran for a few seconds and died. It sounded good while it ran though, i.e. I didn't hear any hissing or anything else weird. On subsequent attempts to start it wouldn't so much as cough, except once after I let it sit for a few minutes. Checked it with a timing light; it's getting plenty of spark.

The fuel bowl fills up fine, the float doesn't have any leaks. I'm starting to wonder if my jets are clogged, and just enough gas gets through to run it on vapors for a moment. Otherwise, I'm all out of ideas.

[geezer#99]

Maybe you need to re-time your motor.
And figure out how to post some pics. We're workin' in the dark here!!

[Ride The Snake!]

Hmm, maybe. I don't know enough about the specifics of bad ignition timing symptoms to say. I know that prior to my carb rebuild, the truck tended to run rich. Months ago the distributor crapped out on me and my roommate rebuilt it, and we dialed in the timing pretty good. I think starting 8 degrees advance and total advance went up to 30-34 degrees or so (the gauge on the crank pulley only goes to +/-12 degrees, so I was estimating the total timing).

I've tried mildly retarding the timing since reinstalling the rebuilt carb, and after no luck put it back where it was, but I couldn't really advance it any farther than it was before because of the way I had the thing oriented. The diaphragm for the vacuum advance is bumping into part of the intake manifold. I guess I should try removing the dizzy shaft and setting it back down where there's more room to adjust the timing.

Will timing that is too retarded cause hard starting more than over-advanced timing? I know late timing can make a motor run hot, which mine seemed to do the one time I had it going since this all started.

I still wonder if the motor is even getting gas through the jets in sufficient quantity to run, because it starts and then dies, like it's getting just enough fuel vapors to run once for a moment. If the timing is accurate enough for it to start, that shouldn't cause it to die at idle, right?

[Ride The Snake!]

Originally Posted by geezer#99

Maybe you need to re-time your motor.
And figure out how to post some pics. We're workin' in the dark here!!

Yeah, I don't understand why I can't post pictures. On my forum account there's the option to upload images, which I did. It creates a url on the site where they're stored I guess, and I copied and pasted that url into my post. I was able to open said links, even when logged out of the forum! So weird...

[geezer#99]

You could cheat on the trying to advance thing without lifting the distributor. Just move all your cap wires CW one hole. Start at #1 and move it to where #8 is and work back around. Firing order is 18436572 if you don't remember.
The reason it starts and dies could be lack of sufficient choke and a cold intake. It goes lean and dies cause the fuel isn't vaporized.

[LEEVON]

Originally Posted by truckster

Summit Racing has remanufactured Quadrajets starting at about $270. They'll set them up for your application:

http://www.summitracing.com/search/P...t&autoview=SKU

This right here. I'm on my 4th install...love 'em.

[geezer#99]

Originally Posted by GASoline71

So the OP has a 2 bbl carb and everybody keeps recommending 4 bbls? Just trying to understand here...

Gary

Ya Gary!! I don't get either. Everybody wants to sell him a different carb but not to many want to help him get the one he's got running.

[Ride The Snake!]

Originally Posted by geezer#99

Ya Gary!! I don't get either. Everybody wants to sell him a different carb but not to many want to help him get the one he's got running.

It might be because at the time I posted this thread I was thinking I'd have to replace my carb, so i titled it as such. Now I'm more determined to try to get this one running.

Seems you sent me a PM but my pop-up blocker wouldn't let me see it. Let me try again.

[Ride The Snake!]

Originally Posted by geezer#99

You could cheat on the trying to advance thing without lifting the distributor. Just move all your cap wires CW one hole. Start at #1 and move it to where #8 is and work back around. Firing order is 18436572 if you don't remember.
The reason it starts and dies could be lack of sufficient choke and a cold intake. It goes lean and dies cause the fuel isn't vaporized.

Yeah my choke linkage is nonexistent, but I tried closing the choke by hand while my dad cranked it. No go. I never bothered using the choke before, and the truck never had any problems starting cold. It actually tended to have somewhat hard starting when it was hot.