Rebuilt Thermoquad issue -- It has to be primed before start each time

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purplehazenils

purplehazenils

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-----The rebuild:-----
So I rebuilt my Thermoquad a while back, the main well O-rings/X-rings were bad but I bought a whole kit to to change out other gaskets etc while I was at it.

I did the rebuild to about 85%, I didnt disassemble absolutely everything but I changed the main gaskets, rings, accelerator pump and some other stuff. I also did the adjustments to spec, it wasnt that far off to begin with.

----- The problem: -----
I cant remember if it was a problem from the start or if it happened a few days after use ... Anyway, the car runs and drives fine but you have to prime the engine/carburetor before you start it each time. Sometimes it will start without priming but if it dies when you put it in gear you have to prime it to get it going again.

I noticed that the two nozzles in the primaries which squirt fuel when you pump the carb dont squirt fuel anymore so I assume this is the problem. But what should I be looking for when I disassemble again? A somehow jammed accelerator pump?
 
Did you put the check valve back in under the squirter nozzles
 
there is a dinky tube that feeds the squirters from the pump well, it may have come off or become clogged. remove shooter and pump carb to see if anything comes out.
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pishta said:
there is a dinky tube that feeds the squirters from the pump well, it may have come off or become clogged. remove shooter and pump carb to see if anything comes out.
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Good point that would cause it right? The nozzles are fed from the accelerator pump which is fed from that hose?
I replaced the hose with a new one, it was one snug but who knows if it came off somehow..?
 
You seem unfamiliar with what you did to the carburetor even by your own standards, so trying to get help from us here is going to be difficult. You don't seem to even know what the accelerator squirter check valve is, we have no way to know if you removed it, or put it back......or even if it was there to begin with. Thermoquads can give even a seasoned professional a tough time, so they can and will give a novice hell.

I mean no offense by any of this, just trying to get you to understand, coming on here saying "hay guys, I sorta half way rebuilt my carburetor, now what's wrong?" is going to be difficult at best. And it's not like we have a member here conveniently located to come help you in Sweden.

If you could be a little more clear about what specifically you did and did not do, that would be a start.
 
Do you use a rebuild instruction sheet? It would show where and what the parts are. I'll bet the accelerator pump feed tube is damaged or disconnected.
 
RustyRatRod said:
You seem unfamiliar with what you did to the carburetor even by your own standards, so trying to get help from us here is going to be difficult. You don't seem to even know what the accelerator squirter check valve is, we have no way to know if you removed it, or put it back......or even if it was there to begin with. Thermoquads can give even a seasoned professional a tough time, so they can and will give a novice hell.

I mean no offense by any of this, just trying to get you to understand, coming on here saying "hay guys, I sorta half way rebuilt my carburetor, now what's wrong?" is going to be difficult at best. And it's not like we have a member here conveniently located to come help you in Sweden.

If you could be a little more clear about what specifically you did and did not do, that would be a start.
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Yeah your right I have absolutely no idea what an accelerator squirter check valve is. If you google "accelerator squirter check valve thermoquad" you get nothing and its not that easy to find out.
Its not easy to help me either because Im not sure what anything is called. But symptoms can sometimes be linked to causes or areas at least.
Thats how I found out what was wrong with the carb in the first place I said hey my Thermoquad is all rich or something, someone mentioned o-rings/x-rings which was a huge help because I checked them and they were crap and the cause.
Like from this thread so far I have had my "suspicion" that this has something to do with the accelerator pump verified and got the tip to check the pipe that feeds it. I know what area to look at now :)
 
MoparLeo said:
Do you use a rebuild instruction sheet? It would show where and what the parts are. I'll bet the accelerator pump feed tube is damaged or disconnected.
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Yes I did, will check on that when I get access to it.
 
I'm fore warning you right now , if you have to prime it first , one of these times it will backfire and very possibly catch your car on fire , I know first hand. I've had firebog. make sure you have the air cleaner on or a fire extinguisher handy. get it fixed right.
 
A common issue with the Thermoquad plastic housings is the 2 little 'oilpans' / buckets at the bottom start leaking and let fuel drain from the float chambers straight into the manifold.
The fix is to crack them loose and reattach them with JB-Weld or something like that.

Pic07.jpg
 
BigBlockMopar said:
A common issue with the Thermoquad plastic housings is the 2 little 'oilpans' / buckets at the bottom start leaking and let fuel drain from the float chambers straight into the manifold.
The fix is to crack them loose and reattach them with JB-Weld or something like that.

View attachment 1715187175
Click to expand...

Naturally with my luck I had to do that, they were leaking baddd :eek:

DSC_1258.JPG


DSC_1261.JPG
 
Bulldozer said:
I'm fore warning you right now , if you have to prime it first , one of these times it will backfire and very possibly catch your car on fire , I know first hand. I've had firebog. make sure you have the air cleaner on or a fire extinguisher handy. get it fixed right.
Click to expand...

Damn it never crossed my mind.. Thanks for the tip!
 
76 is going to look like a little pointed pellet: the point goes down. It prevents the discharge tube from draining between squirts and also prevents the air stream from pulling fuel out the squirter at high engine speed. If your missing it, it wont give you an immediate shot as it will allow air to be drawn into the pump circuit when it "reloads" but it will still give you a shot.
 
Get a book titled,
“How to Rebuild Carter/Edelbrock carbs”
 
purplehazenils said:
I cant remember if it was a problem from the start or if it happened a few days after use ... Anyway, the car runs and drives fine but you have to prime the engine/carburetor before you start it each time. Sometimes it will start without priming but if it dies when you put it in gear you have to prime it to get it going again.

I noticed that the two nozzles in the primaries which squirt fuel when you pump the carb dont squirt fuel anymore so I assume this is the problem. But what should I be looking for when I disassemble again? A somehow jammed accelerator pump?
Click to expand...

Hang on guys, these are two different problems yet the source may be the same.

The car runs and drives fine say the pump circuit works once the bowls are full.
The second part is actually the problem; where is the gas draining to, at shut down. My guess is those little pans are not sealed, and the gas went into the intake, and you know where it goes from there. This also explains #3, it dies when you put it into gear.

I doubt you can seal those pans by globbing JB on the outside. Like previous poster BigBlockMopar said, " you have to crack them loose" and put the sealer where it needs to be. Then test them before you put it all back together. Actually since you have already applied the JB, take the bowl off and test it; Yes with gas, or alcohol.
 
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1. Squirter Nozzle
I never actually removed it during the "rebuild" but I checked and it was in place. With mouth i could blow air though the hose so it exited though the nozzles in the primaries but couldn't suck air back. Pic. 1

2. Tube
Was not damaged, disconnected or clogged Pic.2

3. Mini "oil pans" for fuel
Well spotted AJ/FormS, I did not break them off I just globbed fuel on the outside after roughing up the surface with a dremel.
I dried everything up, filled them with gasoline and waited 15 minutes but not a drop of moisture came through Pic. 3

Anything I could have missed? :realcrazy:

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Cracked bowl then?
There's only supposed to be a few ways out of the bowls; UP the main wells, and UP the pump circuit.
You seem to have them covered.
I suppose you could fill the bowls, and watch for fuel escaping somewhere that it shouldn't be. But it's tricky cuz at 70plus degrees, the fuel flashes away pretty fast. I think I'd try it with solvent,mineral spirits or paint thinner, or even diesel. Yeah diesel; it will leave a tell-tale greasy surface behind. Keep the liquid level to about 1/2"below the top of the bowls, cuz diesel will climb up the sides,by what I think is called capillary action.
So will the other fuels but they will evaporate before climbing over the side. Diesel is way slower to evaporate, so it will climb over if the level is too high, and of course that would give you a false sign. Diesel will also be slower to migrate thru a crack, so give it an hour or so.
 
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AJ/FormS said:
Cracked bowl then?
There's only supposed to be a few ways out of the bowls; UP the main wells, and UP the pump circuit.
You seem to have them covered.
I suppose you could fill the bowls, and watch for fuel escaping somewhere that it shouldn't be. But it's tricky cuz at 70plus degrees, the fuel flashes away pretty fast. I think I'd try it with solvent,mineral spirits or paint thinner, or even diesel. Yeah diesel; it will leave a tell-tale greasy surface behind. Keep the liquid level to about 1/2"below the top of the bowls, cuz diesel will climb up the sides,by what I think is called capillary action.
So will the other fuels but they will evaporate before climbing over the side. Diesel is way slower to evaporate, so it will climb over if the level is too high, and of course that would give you a false sign. Diesel will also be slower to migrate thru a crack, so give it an hour or so.
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Cool, I filled the "fuel oil pans" and the bowls with diesel this time just enough so it wont climb the walls. Going to leave it overnight and see if anything comes through. The whole plastic resin part looks very good, couldn't fins any cracks anywhere..
 
If only the oilpans are full, then your test will only prove the oilpans. I was suggesting you fill the entire float-bowl chamber. Oh nevermind I reread your post, and noticed the "and the bowls" this time
The oilpans themselves I would test with gas. This will give almost instant results.You'll see the JB turn color and change it's sheen, as it become moist.

Here's another test I just dreamed up; I have never done it. You should be able to invert the black body and submerge it in a pail of water, and if there is a crack, I wonder if the trapped air inside wouldn't find it and bubble out.
 
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I once had a bad case of this Thermoquad fuel 'oilpan' leakage when the engine would start to idle very rich without possibility to lean it out anymore.
When opened up shortly after, I noticed fuel in one of the chambers in the lower base plate where the these oilpans normally reside when the carb is together.
 
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