Thermoquad dry fuel bowl at cold start and restart

[Geoff 2]

[1] Do NOT epoxy the o rings!!!
[2] I am not sure if the o rings are compatible with E fuel. I do NOT use E fuel.
[3] Use fuel resistant epoxy such as Devcon on the pri jet covers. Carefully scrape off the old white epoxy. Roughen the surrounding surface for good adhesion. Finish wipe with Lacquer Thinners. If put big blobs of epoxy on, the gasket will not fit.
[4] As a final test for leaks, fill the bowl to just below the cut out.

 

[Charlied]

[1] Do NOT epoxy the o rings!!!
[2] I am not sure if the o rings are compatible with E fuel. I do NOT use E fuel.
[3] Use fuel resistant epoxy such as Devcon on the pri jet covers. Carefully scrape off the old white epoxy. Roughen the surrounding surface for good adhesion. Finish wipe with Lacquer Thinners. If put big blobs of epoxy on, the gasket will not fit.
[4] As a final test for leaks, fill the bowl to just below the cut out.

Thanks for these tips, much appreciated.
All signs point to O ring failure, hope so. Will get to work on it next week.
E free gas is readily available here so that’s it for the future.
The thing that doesn’t make sense is why plugs not fouled and it doesn’t run rich.
FYI car is 74 Satellite Sebring Plus, big block, 4 spd car, all original. I’m the original owner, first new car I ever bought.

 

[WileERobby]

What is the timeframe between starts ? If I let my 79 sit for a week... it's "crank-it-up" time. The fuel evaporates and I have to give it a squirt to start.

 

[Charlied]

What is the timeframe between starts ? If I let my 79 sit for a week... it's "crank-it-up" time. The fuel evaporates and I have to give it a squirt to start.

Time frame 2 hours.Don’t think fuel can evaporate that fast, so it’s a leak or some how there is a reverse siphoning going on. Frankly, don’t know if that is even possible, just grasping at straws.

 

[WileERobby]

Time frame 2 hours.Don’t think fuel can evaporate that fast, so it’s a leak or some how there is a reverse siphoning going on. Frankly, don’t know if that is even possible, just grasping at straws.

No, that's too short. You got issues going on.

 

[Cranky]

Also from your picture above the S link for the accelerator pump is on backwards. It should look like an S when looking at it from the front. It will affect your pump shot if backwards.

I stole that shot from the internet. I was studying the photo and it dawned on me, forehead slap, it isn't mine. whew.. but that's something to know.

Still have one TQ hanging around for some reason and the S link is on correctly but have had them on backwards before and didn't have any issues with the AP. Did notice that the link has a slight bend in it and can see where it may make a difference if backwards. Been a long time since working on a TQ and yet still learning about them lol. I do know how nice they are when they are tuned right!

 

[Charlied]

No, that's too short. You got issues going on.

Agreed. Has to be a leak. The two primary culprits, cracked fuel bowl, less likely since no evidence of external leakage, or those 2 O rings in the bottom of the bowl, that have been ravaged by ethanol gas.
Sorry to be so dramatic but just frustrated. May have to wait a week to tackle it since air temp close to 100 F all next week and in my garage probably 110 here in Atlanta, GA.

 

[Cranky]

Agreed. Has to be a leak. The two primary culprits, cracked fuel bowl, less likely since no evidence of external leakage, or those 2 O rings in the bottom of the bowl, that have been ravaged by ethanol gas.
Sorry to be so dramatic but just frustrated. May have to wait a week to tackle it since air temp close to 100 F all next week and in my garage probably 110 here in Atlanta, GA.

I was out in my shop today until noon time when the temperature hit 97....

 

[The Capitan]

I use a product called Seal All to seal the lower wells. Did the repair 5 years ago, and still sealed up.

 

[Charlied]

Thanks, where did you buy it?

 

[The Capitan]

Farm and Fleet. Google Seal All. Let it cure for numerous days and it will work well.

 

[Charlied]

Farm and Fleet. Google Seal All. Let it cure for numerous days and it will work well.

Thanks

 

[Geoff 2]

Any fuel resistant epoxy can be used on the fuel wells. I use Devcon. I think a lot of fuel wells get repaired....that are not leaking. Easy to bench test.

 

[Charlied]

Hi Geoff,
So the simple bench test is with the fuel bowl isolated pour fuel into the two bowls and observe watching for a leak stream,correct? If no leaks seen, can I assume problem is the two o rings ?
I meticulously rebuilt the carb awhile ago, ( following Rocky’s road show excellent video) cleaning every part, and all new gaskets and seals.
I have a bad habit of over complicating things, best to use the KISS method , keep it simple, stupid !
Thanks

 

[Geoff 2]

Yes, that is how to do it. Level bench, carefully pour in some fuel into each bowl to cover the o ring holes, but not high enough to run out from the cut outs.

 

[eldubb440]

I use Marine-Tex 2 part epoxy on the lower bowls when I rebuild TQ's. Not cheap compared to JB weld but it works well.

Amazon product ASIN B000Y8A06C

"the mighty repair kit" ....... was turned onto it in the early 80s. there's been a can of grey on my bench ever since

 

[Charlied]

Yes, that is how to do it. Level bench, carefully pour in some fuel into each bowl to cover the o ring holes, but not high enough to run out from the cut outs.

Got it .Thanks

 

[Jonas Nordstrom]

Marine tex to re-glue the wells, then add a layer of seal all. Careful to not make the glue too big as it can hit the sides of the base-plate when assembling.
Test by putting the bowl on a white paper with a nut under the rear of the bowl to keep it level, if it leaks you will see dark spots on the paper quite quick.

I usually clean the base for the o-rings and then add a little gasgacinch there and gently press the o-ring down, centering it.
Let it dry before assembling.

Also, plug that bowl vent when having the car in the garage to keep the gas from evaporate. Open it up when go out driving for quicker starts when hot.

The rod-tree center screw is such a cool tuning part. I did set the rod tree on my 6322 as factory but needed 1,5 turns richer to reach a perfect cruise Afr.
Fun thing: Ive tuned all types of aftermarket carbs on my engine and many of them got bogs that needed to be addressed.
...but no bogs on my TQs, anywhere.

 

[Charlied]

Marine tex to re-glue the wells, then add a layer of seal all. Careful to not make the glue too big as it can hit the sides of the base-plate when assembling.
Test by putting the bowl on a white paper with a nut under the rear of the bowl to keep it level, if it leaks you will see dark spots on the paper quite quick.

I usually clean the base for the o-rings and then add a little gasgacinch there and gently press the o-ring down, centering it.
Let it dry before assembling.

Also, plug that bowl vent when having the car in the garage to keep the gas from evaporate. Open it up when go out driving for quicker starts when hot.

The rod-tree center screw is such a cool tuning part. I did set the rod tree on my 6322 as factory but needed 1,5 turns richer to reach a perfect cruise Afr.
Fun thing: Ive tuned all types of aftermarket carbs on my engine and many of them got bogs that needed to be addressed.
...but no bogs on my TQs, anywhere.

View attachment 1514479

Thanks for the tips

 

[Charlied]

[1] Do NOT epoxy the o rings!!!
[2] I am not sure if the o rings are compatible with E fuel. I do NOT use E fuel.
[3] Use fuel resistant epoxy such as Devcon on the pri jet covers. Carefully scrape off the old white epoxy. Roughen the surrounding surface for good adhesion. Finish wipe with Lacquer Thinners. If put big blobs of epoxy on, the gasket will not fit.
[4] As a final test for leaks, fill the bowl to just below the cut out.

I’m stumped,tested fuel bowl by adding odorless mineral spirts to bowl as you suggested on level surface checked 2 hrs later surface below dry as a bone (no leak)

Also pulled O rings, surprisingly they were not distorted and flexible.



photo is what I found when I orginally opened it up. You can see the two pools of fuel which is where the bottom of the fuel Bowl sits, if bowl has no leaks how did fuel get there. Would bad fitting O rings do it ?