The function of the choke is to enrich the mixture, when cold. If the choke is still partially closed once the engine is hot, the choke will still enrich the mixture. You state you have fixed this.
Check the oil. If the mixture was so rich as to cause engine damage, the oil will smell gassy, and the level on the dipstick might show overfull.
Since you have corrected a potential major issue; I would: (A) change oil and filter, (B) change spark plugs, and then (C) go drive the vehicle and see what, if anything changes.
Engine state of tune is one determinant for fuel economy, but others include final drive ratio, tire diameter, and driving habits. 7 MPG is a number, but is not necessarily bad, depending on all of the parameters.
EDIT: And I would echo the comment of 389 above to install a hotter thermostat!
Jon
__________________
"Good carburetion is fuelish hot air". 
"The most expensive carburetor is the wrong one given to you by your neighbor".
If you truly believe that "one size fits all" try walking a mile in your spouse's shoes!
Owner of The Carburetor Shop, LLC (of Missouri).
Current caretaker of the remains of Stromberg Caburetor, and custodian of the existing Carter and Kingston carburetor drawings.
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