How many metering rods in a thermo-quad?

[Loa]

Hello,

I'm in the process of rebuilding my (first) thermo-quad (6138) and discovered that there was only one metering rod, despite the fact that there is a hole for a second one. Is one normal, or is a second one missing?

Thanks

Loa

[1 Wild R/T]

Should be two...

[Loa]

That's what I thought. Damn... Now I have to try and find only one.

Thanks.

[brasil]

http://quadrajetparts.com/thermo-quad-rods-c-299_158_161_166.html?osCsid=42192c754928efdf3fa9d91bc2bc9f4c

the 1966 Rods   are the best to use !   I have a trick kit...with a lot of rods...but hands down  the 1966 ist the  ONE

Greetings Juergen

[Bullitt-]

get ya one of these better pump diaphragms while your at it
http://quadrajetparts.com/carter-accelerator-pump-double-1316-alcohol-resistant-p-770.html

[Loa]

Thanks for the tip!  I'll order them right now.

[brasil]

@ LOA   ist your engine a 340 ? If so....use the 1966 rods with 95  or 96 jets... and 137 secondaries...  also like bullit said  change the accel. pump diaphragm.... then your are good to go...

Good luck !

Greetings Juergen

[Loa]

Yes it's a 340 (1972). While cleaning the carb I tried removing the jets to see what size they were, but they were mightily stuck in the main body. I still haven't been able to remove them. Carb cleaner didn't seem to help.

Any suggestions?

[Bullitt-]

Yes it's a 340 (1972). While cleaning the carb I tried removing the jets to see what size they were, but they were mightily stuck in the main body. I still haven't been able to remove them. Carb cleaner didn't seem to help.

Any suggestions?

You don't need to remove them unless your replacing (I've never taken one out)...
You need a small drill set to slip in the opening to see what the size is...

[Loa]

Using the small drills, I found that they're 3/32 of an inch.

Is that a decent size for a (I think) stock 1972 340?

Thanks

[Bullitt-]

.092" primary jet I'm assuming was stock.. with the 1966 Metering rods would be as good a starting place as any.
Until your into fine tuning with an air/fuel meter you probably wouldn't know the difference..

http://www.carbkitsource.com/carbs/tech/Carter/pages/tqguide-Vaanth.html

Be especially careful to properly set the Step-Up Piston as well as the Secondary Air Door....tricky
Double check all measurements as changing one can impact another...
I found setting the Throttle Stop Screw with the carb off so the Idle Transfer Slots were correct(square) solved a lot of issues I had... Then adjusted timing for Idle Speed(sounds crazy I know) 
http://www.carburetor-parts.com/assets/Carter_ThermoQuad_Carburetor.pdf

[brasil]

.. 6138 TQ  had     0.095  ( 4095 ) primary   0.137  ( 5137 )  secondary  jets   the rods were the 1940      but with the 1966  rods... the mixture is a little richer...
0.072  / 0.060 / 0.045    vs    0.067  / 0.052 / 0.045      ( 1940 vs 1966  rods )

the 1940 rods are hard to find...btw..



Greetings Juergen

[Loa]

Thanks for the added info. I'll download the two guides. I did take a lot of pics before disassembling it, and I'm glad I did: I was planning on doing the entire job during the same day, but the missing metering rod halted that plan.

My new plan, as far as adjustments are concerned, is to reassemble it exactly as it was and see if it fires. Then I'll try to optimize it.

Thanks