The Carter Thermoquad carburetor is a very versatile unit, but you need a special tool to adjust the preload spring for the secondary air door to unlock its full potential. This is an improved tool over other designs and has a very precise fit into the lock screw on the TQ carburetor.
Our first design on this tool was around $24. It was designed much like all the other tools available on the internet. I found it had limitations when you get to a locking nut that has damaged corners. Those are usually the ones that people have tried to loosen off with a normal screwdriver or one of the cheaper tools and it just slips off, rounding the corners.
So this deluxe tool was developed. Anyone who purchased the first style who has not been contacted by me (I emailed everyone who purchased, but some bounced back) can contact me for the new style at NO CHARGE.
This tool is now $60. It has a ring that centers the tool in the nut, and has a very positive engagement even on damaged locking nuts. Adding this ring needs 6 additional machining steps and takes alot longer to make, and yes it is a pricey little fella.... but it WORKS where others do not.
Built from steel and coated for durable long lasting service.
Thermoquad Air Door Spring Adjusting Tool