Starter pinion gear to flywheel / flex plate spec is 0.60". The voltage issue depends on several things that should be checked anyway from time to time. Voltage drop is the best way to get quick, accurate reading that tell you exactly what is going on. A digital multi-meter (DMM), check battery voltage while a buddy cranks over. If less than 11 volts and no current amp-clamp to check starter draw, do a voltage drop from battery terminal to starter B+. If meter lets a backward, it reads the same, just with a (-) sign in front of it. Clip them on and crank over to supply current as voltage drop requires a circuit have current, or it won't work. 0.400 volts or 1/2 volt as this is a high amp circuit, like a snow plow, alternator when full-fielded or lift-gate. The voltage to the "S" terminal at the solenoid has a long trip to make. Voltage drop works here also, even if voltage is pulled low during cranking. A voltage drop from battery to large fuses at relay center should be low like 0.050 - 0.090 volts. If not, clean and use dielectric grease upon assembly. Voltage drop from fuse/relay center to starter switch with same low drop. If not, back track connections to perhaps bulkhead/firewall connector. If ok, check voltage drop from ignition switch to PPL wire on starter solenoid. Once again, the lower the better, but size of wire and length plus condition effects voltage loss. Has this been intermittent, just one day ever since or since part change? A current amp-clamp would show a lot about the condition of the starter with the acceptation of engine mechanical. YouTube has good sources to learn, but I feel naked without my Fluke 87 type 5. This meter has a "Min-Max" feature that records the reading. Many lower priced amp-clamp with digital read out, tested against my Fluke amp-clamp where very close and accurate. They are very handy to have, but a good DMM and your ability to do a voltage drop will help a bunch. Best of luck!
