[n4mwd]

No you didn't buy a junk bike.

How many miles on it? If the miles are unusually low, expect carb problems. If high, there could be other problems. Unusually low means less than 7K miles on a bike that old. Depending on the mileage, you may also need to do a valve adjustment. This is due every 6K miles.

The fact that you said he was trying to jump it sounds like there may be an undisclosed electrical problem. If he was jumping from a running car, he may have burned it out right in front of you. Keep an eye on your charging circuit to make sure it still works.

Also, don't use the kill switch to stop the engine. That is for emergencies. It does not shut off the headlight and runs your battery down. Use the key.

Like the others said, make sure you know how to use the choke properly. It sounds like from your comments that you were having trouble mostly when it was cold.

Whether you can do the work yourself depends greatly on your mechanical aptitude.