I have a Onan 6500LP generator which has twice recently stopped working. On dismantling it we found the vapouriser and the regultor were fairly full of a brown emulsified oil substance. Initially we just cleaned everything out and assembled it again.LPG apppears clean upto Vapouriser. This second time we wonder if it may be as a result of reaction of gas with the metal used on the vapouriser (looks like steel), The vapouriser pipe was also held against the exhause pipe with jubilee clips. So have replaced it with a copper one, and moved it slightly away to avoid possible hotspots. If this doesn't work, any sugggestions? It is 4 years old and only done about 250 hours use.