Carter Thermoquad Jets

G

gavin2337

New member
I bought a rebuilt thermoquad years ago in texas and now I live at 9300ft in Colorado. I'm wondering where and what size jets I should order to lean this thing out a little as it runs rather Rich.
Thanks for any help
gavin sollberger

'75 Scout II
345ci, carter thermoquad, stan's headers, new exhaust
dui ignition, t-18, d20, d44's with 3.54's, 4" springs on 32"s
 
Hey
what part of Colorado are you in? I am in denver....
Not sure on the thermoquad, but if you ever switch carbs the edelbrock 1400 has worked good for me
 
First off...have you read through this thread?:

http://www.forums.IHPartsAmerica.com/carb-tech/1390-carter-thermoquad-spreadbore-stuff.html

In post #18 you will find a link I provided that will take you to the definitive tq historical reference/tuning guide on the 'net.

How long has this carb been in actual service, and how long has it been "sitting" with fuel inside (long evaporated) out of service??

Carburetors are not lifetime items, they require periodic maintenance, most especially the smog carbs of the 70's!!

There is some inherent "adjustability" to the tq regarding altitude compensation. And the "last gen" tq in some applications had an add-on module created just for that purpose of altitude compensation since that affected emissions and the vehicle was required to maintain emissions for the life of the "emissions warranty" period. As for the federal requirement, that point was 5,000ft.

Don't even think of trying to adapt some crap like that to your tq, it won't work, for all intents and purposes, those two carb designs are not the same!

The most common root cause of what you describe is due to fuel bowl leakage and/or the non-sealing of the internal seals (in some versions a type of "o" ring). Basically, raw liquid is dumping out the bottom of the fuel bowl anytime fuel is present inside the bowl. And/or...the liquid metering systems (jets and rods) are being simply bypassed due to deterioration of the seals.

The tq carburetor must be totally disassembled to change any "jets" anyway, why not rebuild it properly?? Then you have a baseline for tuning purposes if needed and if you can find the range of hard parts for achieving any altitude compensation.
 
I'm in crested butte and the Scout usually stays in the valley up here. Sometimes it makes it to the front range but not very often. The carb was in service for a few years then it had a five year break with random starts and drives. Since last winter it's been my daily driver and it runs well. Just recently I started getting worse (2-3mpg) mileage and there's a bunch of black grime on the front of the carb. I bet it is time for a full rebuild again or maybe a new carb. Thanks for the help
and micheal I did read your full thread on the carter, guess I must have missed the link, sorry.
 
That bad of gas miliage and that much black smoke, I would say your carb needs more then a jet change, either rebulit or replace. Crested butte is a fun place, if you get a chance check out schofiled pass in the summer...
 
It runs pretty good though. I think I'll try the rebuild or is there a better replacement? Yeah I've been in the butte for 7 years now so I've played all over the place.that's why I'm still here.
 
gavin2337 said:
I'm in crested butte and the Scout usually stays in the valley up here. Sometimes it makes it to the front range but not very often. The carb was in service for a few years then it had a five year break with random starts and drives. Since last winter it's been my daily driver and it runs well. Just recently I started getting worse (2-3mpg) mileage and there's a bunch of black grime on the front of the carb. I bet it is time for a full rebuild again or maybe a new carb. Thanks for the help
and micheal I did read your full thread on the carter, guess I must have missed the link, sorry.
Click to expand...

A "new" tq for an IH app? Good luck! A mint tq for some chryslers (resto only) with the right numbers and an id tag can bring well into four figures.

So far, the few "commercial" remanned tq carbs I've done have all been garbage inside with the wrong parts. That's why they were sent to me after being purchased by IH folks off the 'net and finding out the vendors for those items don't understand the meaning of the term "customer service" or "warranty". In actuality, their quality statement needs to read "buyer beware".

There are hundreds of variations of the tq...IH used only a very few model numbers in very small quantity as compared to any other oem. And there are two completely different versions of the tq also, the "early" and then the later version, virtually no parts interchange between the two design series. That is why the commercial remanners have a very hard time getting these things right...it's hard enough for me to git 'em right and I spend far much time on doing so.

If you have a tq core that was good at one time, then it can be made good again if done correctly.

I keep telling you folks...with today's shit-for gasoline, the typical service life of any carburetor in daily service is two years before they quickly slide downhill!

And efi does not solve that problem. E10 scruus over efi systems just as bad as it scruus with carbs, just different manifestation and parts! Anything inside the entire fuel system that sees e10 is gonna eventually be scruud in some fashion. Some of these electric in-tank fuel pumps for efi run over $1000 to replace!
 
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