Bad ammeter causing cranking problems?

[Ranham]

I'm new here, I'm putting a model a back together for a friend. I have never worked on a model a but I'm pretty mechanically inclined. My problem is it wasn't cranking so I have checked everything out and I have 6.3 volts everywhere except the - side of the coil where it is 5.6. I took a wire and hooked it straight to the coil and it cranks. My question is can a bad ammeter cause this not to crank? Thanks