MotorCraft 2150 carb. I noticed hesitation, in some cases almost to the point of stalling the engine, when stepping on the gas pulling away when the light turns green. There does seem to be something wrong with the accelerator pump or the mechanism that works the accelerate pump arm. Isn’t the accelerator pump arm supposed to be out, and only pulls in when you step on the gas ? For some reason that arm is pulled in all the time. It never goes out.
The configuration on my carb is the accel pump arm is connected to the throttle via a metal rod; but it’s not a direct connection, the throttle end of that rod doesn’t connect directly to the throttle arm (the thing on the carb that moves when you step on the accelerator pedal, and which is connected to the throttle plate shaft). Instead there’s a spring that goes around the throttle plate shaft, wedged between the throttle arm and the carb, and that spring is connected to its own arm, which the accelerator pump rod connects to.
So the problem seems to be when I step on the gas, the throttle arm is moving like it should, but the arm the accelerator pump is linked to doesn’t move. So I get no accelerator pump action. I don’t see how moving the throttle arm would move the spring’ed arm in the first place. But it must have moved before, as I had no acceleration problem before. If it is by friction, I don’t see anyway to adjust the amount of friction. I’m sort of thinking the problem is there’s a broken spring in the accelerator pump, and that spring is supposed to return the accelerate pump arm to the “out” position.
What do you think? Anyone seen this configuration before? I can’t decide if it is the accelerator pump that is broken, or the spring mechanism over by the throttle shaft is broken.