Air cooled versus liquid cooled has naught to do with what kind of fuel it
takes.

Christopher A. Young
Learn more about Jesus
www.lds.org
..

wrote in message
...

They are as loud as any typical small air cooled engine. If you want
quiet you have to move up to a commercial grade liquid cooled model.

I wouldn't expect the same engine to have any significant
difference in noise based on what fuel you put in it. You
do get about 20% less power out of the same engine if
it runs on nat gas versus gasoline. That should equate to
some difference in noise, but doubt it's significant.