Well, there's good news and there is bad news.
The good news is that my little lawnmower battery was actually capable of cranking the big 2.5L. Well, for a while anyway
The bad news is that she didn't fire

And I had a coolant leak (I'm sure the sarcasm won't be wasted on you aircooled guys

)
Anyway, I've put the battery back on the charger, and gotta figure out how to troubleshoot this..... I guess I'll start at the basics, fuel and spark, and just work from there.....
Stay tuned.....
Rob.