First, remove the idle screw (large screw with lock nut underneath front edge of intake) Clean thoroughly with carb cleaner. Check aux air valve to make sure it is closed when warm and open when cold. make sure that hoses are not split or loose.

Use some carb cleaner to clean deposits from throttle plate and bore - use small toothbrush to help. Don't try to remove the intake manifold unless you are ready to install new manifold gaskets.

To adjust throttle plate: loosen lock nut on throttle plate stop screw. Loosen stop screw until the throttle plate is fully closed (as evidenced by cable puley sector no longer moving. Then turn screw in until it just contacts the throttle plate lever, but does not move it. Then turn the screw 1/4 turn further and lock. Then replace idle screw into now clean passage and screw in to original setting.

Remove plug from throttle switch and connect ohm meter to terminals 14 and 17 of the switch. Adjust the switch so that the meter reads 0 ohms. Then place a 0.02" feeler gage under the throttle stop screw - the meter should read infinity. Adjust so that it reliably reads 0 without the feeler and infinity with it. Start the engine and set the idle with the idle screw to ~950 rpm. For more info, see Shade Tree Mechanic article on D-Jet systems in Sep/Oct 97 Rolling. --
Steve Seekins