Trevor, I guess that really didn't answer your question. To be more specific, No. I don't think generator "noise" spooks the fish unless it's transmitted through the boat as vibration.

However, (there's always a catch) If the body of water you are fishing is not used to the sound of gas motors (ie: no outboards). Then yes even the quietest generator will spook them. We had the opportunity to fishsome trolling motor only lakes at night. We took the generator and didn't see a fish in lakes that arelousy with them.

Worst thing about a loud generator is it's obnoxious to be around. You won't like it. And if there are people near the body of water you're fishing, they definately won't like it.

Good news is that as KBI says, a quiet genny is not that expensive anymore. You should be able to find one < $300 that is reasonably quiet.

Good luck.