my propane generator won't start

I never tried running on gasoline, because I did not want to contaminate it. I wanted this generator to run only on propane. I used to have a gasoline generator but I had to  get it serviced each year. I wanted to avoid that, so I purchased this propane generator. When I mentioned "intake filter", that's what I thought the repair guy said, but he might have meant something else. I just remember the word filter, not exactly what kind.