Predator 420 acceleration

[Colwllce]

Trying to figure out this motor. I have the adjustable idle mixture carb in ti. Im trying to figure out what the problem might be. After it warms it idles with the speed screw all the way out. Also i have to. Pump the accelerator from low rpm’s or it will just die on me then it will take off. Runs better when going uphill with a load on engine and when getting on it...

[Shepard]

Do you have a throttle return spring?

[slonomo]

If the screw is toward the intake side of the carb, it's a pilot air screw and adjusts the amount of air allowed into the pilot circuit.

Ideally, your pilot air screw should be in the 1 turn to 3 turns out range.

More than 3 turns out, the pilot jet is too large, you need less fuel.

Less than 1 turn out, the pilot jet is too small, you need more fuel.

Now, if the screw is toward the rear of the carb, then it's a pilot fuel screw. All the adjustments are opposite. Turning the screw adjusts the amount of fuel allowed into the pilot circuit.

[slonomo]

Also it sounds like your "idle speed screw" is not set properly. I'm not familiar with the clone carbs, but usually a carb should start and idle with the butterfly closed. There are air cutouts or holes in the butterfly that allow enough air in to start and idle. But these carbs are usually made for equipment that run in the 2000 rpm and up range, so maybe that's not true in this case? Correct me if I'm wrong, but isn't that the issue with the factory clone and vtwin carbs? They aren't made to idle less than 2000 rpm? I could be wrong.