Make sure to check your chain stretch. If the pump was that far retarded it might be a lot. Try to also acertain why the drip test did not function for you. Read what is available.
At the moment I am not sure why it did not. I guess if you could not reach the slow drip point it would be signifigant. Yet you indicate it was well back in the adjustment slot when you stopped trying to adjust your pump. All your forward movement beyond the original position the pump was in was just to make up for the stretch of the chain I think. Do not ignore it as it may be really excessive. If that proves so and you land up changing the chain all should work out well. You will have to borrow or buy a dial gauge and stand if you do not own one to check it. Harbour freights cheapie is acceptable for this.
If the chain turns out to have acceptable stretch you can go back to completing the drip test. You might land up moving the pump by a front spline movement. One chain tooth would be too great a movement.