You get that part in the gym leaders building in the rubber tube.This is in Cerulean City
At the Power Plant.
you go to the cerulean gym by the floaties on the left after take it back to power plant
he gives you the missing machine part for the generator at the power plant :) hope i helped :D
after beating the gym leader misty, go down the stairs of the gym, go left and press A on the rubber rings, this is where the machine part is for the power plant.
You talk to the boss and he will say that somebody stole a part from the generator, when you return the part, he will give you the TM Zap Cannon. You can also now take the train from Saffron to Goldenrod.
In a inertube.
Battle Misty
you buy it .
You find it in M.T Silver Cave
yes it is by the power plant after u bet team rocket and get the part back
you can;t because she will never be there until you get the part to the power plant
after you get the power plant missing part back to the plant it should be running if you need help go to serebii.net for a walkthrough