SKN,
About the wood cladding on the boiler. On the Heretage engine there's also a layer of insulation under that wood. Does it help conserve heat? Guess it has to to some extent, but doesn't mean much by way of performance. I figure it's more for looks than anything. I'm sure theres a way to put a throttle on a small steam engine but I doubt if it's gonna be a simple thing to do (I wish!). Usually it's all or nothing.
- 'Doc