As the load increases, vacuum drops, and the transfers should be supplying more fuel. But with the power-piston sucked down,sooner or later, the the circuit stalls and cannot keep up with the demand. So it goes lean.
What I meant was that the transfers ought to be supplying more fuel, but they can't because the metering rod cruise step is the limiting factor.
I'm assuming that when OP hits the bottom of the hill, the carb is still on the transfers, cuz Op talks about "light acceleration" in the same sentence. So this is transitioning from a mid-point on the transfers to a higher point on the transfers with the power valve still closed, and not yet up on the booster.
I guess it could happen that with a less powerful engine than mine (low-rpm) Op's engine could be up on the mains; that thought just never occurred to me,lol.
But doing the test as I outlined IMO would prove it,one way or the other. In any case, I get what you are saying. and
I could be wrong,lol.
The more I think about it, the more I think that I am wrong,lol.
But then the test would be invalid as well. Daymn, that hurts..
