Where is the idle speed adjustment on a 1974 85 HP Mercury carbeurated motor?

[glastron4452]

Can someone please tell me where the idle adjustment screw is on a 1974 Thunderbolt 85 hp motor is located?Thanks

[Chris1956]

GRF, That model has two carbs. Each has a single mixture adjustment screw on the right side of the air horn, at about the 2 o'clock position. CounterClockwise richens the mixture, CW leans the mixture. If you want to adjust the speed of the idle, the throttle cable barrel and perhaps the idle stop screw need to be adjusted. The throttle cable barrel is located on the bottom right side of the motor, where the cable enters the engine cowling. The idle stop screw is above the distributor (if you have one on that model), and is marked as "idle stop".