[carbking]

Several things come to mind:

(1) I would agree with Jim (Old Man Taylor) about the seal of the throttles on the end carbs. Check this first.

(2) It could also be ethanol fuel, which is becoming more and more prevalent. We suggest opening the idle tubes by 0.002 inch over stock to compensate for the lower caloric content of the ethanol.

(3) Take a close look at the center carburetor. You did not specify in your initial post much about your car. Automatic? 4 Speed? Original carbs? Non-original carbs??? Many enthusiasts seem to feel that any two-barrel will work, or non-original carbs with repro throttle bases will work (and sometimes they will); but GM did NOT make all of those different parts just to reduce the stockholders profits.

(3A) A four speed car should NOT have a center carb with a hot idle compensator. It can cause a poor idle hot.

(3B) An automatic car SHOULD have a hot idle compensator. Lack of the compensator can cause a poor idle hot.

(3C) Take a look at this picture:

http://www.thecarburetorshop.com/Hotidle2.jpg

ALL 1965 center carburetors should have a throttle body gasket similar (not quite exact) to the one on the upper right with the cutouts. USE OF THE GASKET ON THE LOWER RIGHT CAN CAUSE HOT IDLE ISSUES! Many think the upper right gasket will cause a vacuum leak. This thought is totally erroneous, as the cutouts are above the throttle plates. The cutout area is necessary to bleed excessive fuel pressure when hot at idle from the venturi/throttle area on some carburetors, and the 1965 tripower center is one. The end carbs (at least in 1965) should use the sealing gaskets similar to the one on the lower right.

Just a few things to check.

Jon.