After searching the web for a while, I found the best reviews and prices at US Carbs
http://www.motorsnorkel.com/They have a new invention called a snorkel that basically injects the gas via a small pilot tube built into a gasket under the carb. This allows you to retain all of the original linkage and air cleaners of the OEM. They also have older kits available on ebay and in their clearance section that mount in front of the carb and may require cutting the frame and relocating the air cleaner. The obsolete lits arte greatly discounted.
The kit I bought has you drill out the existing carb and install a new main jet that the gas line connects directly to. I will throw away the float bowl and fuel tank. If I should ever what to go back to gasoline, a new carb is available on ebay for $16.
The dedicated LP kit I bought was $169 including shipping. I still need to buy a primary regulator, available at ACE for $18. This whole thing will end up costing about $200
I will never have to flush out or rebuild another dirty carb, replaced a fouled plug or worry about stale fuel or spills again....AND...I will tell everyone gawking that I am using a GREEN aquatic habitat improver