Does anybody know about something like this:
"208 generator that was used in ww2 to start up the bombers."

I know someone who knows someone that has one. They are asking about it.

Do you have a picture?

The '208 generator' may refer to a 208V 3-phase generator that may be used for some ground operations, but I doubt they would be involved for start up as a 24V DC electrical system was used on the plane.
As I understand it, US bombers had on-board batteries plus an APU, consisting of a gasoline engine coupled with a 28V DC generator. If ground power was needed, it would be supplied by a 'battery cart' rather than a generator.

Here's an example of (according to the guy in the video at least) a B-29 APU:
https://www.youtube.com/watch?v=M-QV1vC-4kk

My father worked for the USAAF during WW2 and up to about 1961. He "acquired" a battery charger/power unit that apparently was sometimes used to start aircraft. It was on wheels, weighed about 100 lbs, input was 110/120v and output was at 6, 12, or 24 volts and it had big knob to regulate the max current output. The output cables were about 25ft long and bigger than your thumb. It would boost large trucks with ease so I have no doubt that it could start an aircraft engine

[video:youtube]https://youtu.be/ChFGBgvVBtA?t=1291[/video]

B 17 start up showing external power unit.