ThermoQuad Secondary Adjustment

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Does any-one have a simple adjustment proceedure for the secondary spring? My engine is a 440 it has been rebuilt. I am running the stock purple cam ported stock heads that have port matched.
I set the spring using the setting in the rebuild kit. The engine pulls strong to 4500 RPM then strains to reach 5000 RPM. Before the carb rebuild I could run to 6000 RPM with some part throttle hesitation.

 

[demonsizzler]

It is pretty simple:
Loosen the lock collar(do not let the spring tension off too quickly or the spring will end up in the bowl!)while keeping a slot head screwdriver in the center slot. The tension will lessen turning the slot clock-wise and the air door will open vertically. With all the tension off, start turning the slot counter clock-wise and note when the air door closes against the top casting(air door is horizontal/in normal position)and count 1.5 turns which is a factory setting. If your engine produces under 15 in of vacuum, you may need 1 turn more but too many turns extra tension and destroy the spring for good, David.

 

[Cranky]

there's a wealth of info here http://www.thermoquads.com/
They are great carbs once setup and tuned right.