Coleman powermate generator

You will need to check the resisitance of the stator and rotor windings, and also each rotor/ring to ground (IE rotor shaft) All tests to ground should be 0 M ohms, stators vary but typically around 1ohm or so, and rotors approx 20-30ohms

Take the through bolt out of the end of the alternator / rotor shaft. it is a long bolt. The shaft from the engine is tapered and unlikely to just pop off. Find a bolt that will screw into the end of the rotor shaft (hardend) find a metal bar that will slide into the rotor long enough so the bolt tightens down on the bar, it will pop the alternator off the tapered shaft

Take the through bolt out of the end of the alternator / rotor shaft. it is a long bolt. The shaft from the engine is tapered and unlikely to just pop off. Find a bolt that will screw into the end of the rotor shaft (hardend) find a metal bar that will slide into the rotor long enough so the bolt tightens down on the bar, it will pop the alternator off the tapered shaft

Take the through bolt out of the end of the alternator / rotor shaft. it is a long bolt. The shaft from the engine is tapered and unlikely to just pop off. Find a bolt that will screw into the end of the rotor shaft (hardend) find a metal bar that will slide into the rotor long enough so the bolt tightens down on the bar, it will pop the alternator off the tapered shaft

It generally has a long rotor through bolt accessibile from the generator end, this forces the generator rotor onto a tapered shaft on the engine. Once removed the through bolt slide a long bar ion the hole and screw the bolt back in, that will force it off the taper

Unbolt and slide the stator over the rotor exposing it. Then simply unscrew the one bolt holding it to the crank. In my experience you need an impact to get the bolt out with spinning the engine and the rotor may need some negotiation to get off. Try a rubber mallet or a sledge with a block of wood, also may need to use a puller as well. Some come off easy but remember you can only hit a magnet so many times before it begins to lose magnetism.

No there is not a key of any sort between the rotor and crankshaft, to verify you will not find a keyway to put one into on the shaft. Just the end bolt with washer holds it on.

How did you put exciting voltage to brushes? Plus to plus, minus to minus or no mater? 
The condenser can be checked by a capacitance meter or an Ohm meter.
Diodes also by a diode test with a multimeter. Reverse should be infinity, forward 0.5 - 0.7 V.

Most of these require one to insert a bolt in the end of the shaft and use a slide hammer to decouple the rotor from the engine. There is a keyway typically... possibly a Woodruff key.

This is going to sound crazy but....with the bolt hole straight up fill the inside of the rotor shaft where the long mounting bolt passes through with oil. There should be a threaded area right at the bolt hole. Get a bolt to match the tread and then wrap the bolt with teflon pipe tape. Place a rag on the back of the engine and then start rotating the bolt. When it separates you will hear a BANG and the oil will drain onto the back of the motor where hopefully you put the rag. It really does get your attention when it pops loose.

Kelly