Same here, tach comes off the back of the generator.....if the generator is the one designed for the tractor......when buying aftermarket, have to look for one with the rear drive. If you don't have such apparently the PO didn't get the one with it.
On starting, if compression is good it will light right off with no preheat down below freezing for me. Below that I use the slobber. Activation is either a push button on the dash (for my '65), or it was in the key switch between ON and Start: As you rotated the key the dash lights went out in the TS position and then when you rolled on over to Start they came back on which my 4600 had. The thermostart device is on the back side of the intake manifold, a couple of inches back from where the hose connects from the air filter. It has voltage and diesel lines connected. Diesel for the slobber and voltage to get the slobber flowing and igniting...."Great Balls of Fire"....Jerry Lee Lewis....guy was nuts....see the movie where he was doing a concert and set the Grand on fire?????? Don't know how the fire marshall let them get away with filming that one......... Or when he removed the front wall of his house to get his Grand into the living room?