I would love to see a study on how 5 year old threads get brought back up by first time posters. Someone would have to be googling for this very obscure topic and then feel the need to not just comment but actually sign up on a web site and comment.

Next study: watch how many people after this don't read through all the posts and ignore that this is a 5 year old thread.

 

I have been thinking on this for a few weeks, I actually had a really bizarre dream about trying to get my Lawn Boy to run on propane. Oddly enough, a google search puts this thread at the top, even though it is five years old.
I have a couple Kawasaki Invader snowmobiles, they use an oil injection system on the 440LC engine, but instead of mixing the oil with the incoming air/fuel mix, it is injected into the main bearings, then follows passages in the crank to the rod bearing similar to a four stroke. After this, it's slung off and burned with the fuel. I wonder if this would work on propane? The only issue I could see is the possibility of the oil pooling in the crankcase, but then it's pretty much a mist when the thing is whipping around at 8k+. I don't know if propane would color spark plugs like gas, so tuning might be difficult. Imagine the compression ratios and output potential without worrying about detonation, though-