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To separate the engine from the generator head you need to remove the bolts that secure the engine to the frame of the generator. On the very end of the generator opposite the engine there will be a cover that you can remove. Remove that cover and you will find a bolt in the center of the generator rotor. That bolt goes completely through the generator rotor and threads into the crankshaft of the engine. Loosen the bolt a few turns so that it is not touching. You will then use a hammer and a brass punch and give it a few good blows to the end of the bolt to loosen the taper seat. Keep doing this and loosening the bolt a little at a time to separate it.