Generator HELP!

[ripinlips]

My brother-in-law was trying to start his old generator and found that it had problems. So he called me that has little small engine mechanical experience to try and fix it. So I found that the cylinder head appeared cracked and was wondering how much a new one might cost. The company of the generator has a non working website and all the small engine shops are closed till monday, so I figured that good ole' saltycajun's could help. He is already looking at new one's and another question is does anyone own or know anything about propane run generators (or propane and Gasoline)...are they good, bad or dependable, worth it or not??? Any help would be appreciated. Thanks in advance.