Thanks very much, I appreciate the info. Someone told me to avoid ARO's based on ordinary mineral oils but without knowing my way around the market, I really wouldn't have known what to go for.
I think this must have been one of the last of the FZ-91's supplied for retail sale. The store operator said he thought he'd had it in stock for maybe 3 years but that seems odd to me, unless the wholesaler had it in their warehouse for 7 or 8.
AFAIK it's been about 10 or 12 years since these were last in production. He told me he can definitely supply spare seals, diaphragms and so on so I thought it would be a good idea to order at least 1 or 2 sets in now before they're all gone, because if/when the day comes in several years when I need them, it's only going to get harder with time to track them down. I don't think it's worth stripping it down to check all these just in case, because as stated this engine has never been fuelled or run. Yes, it turns over no problem if I fit a prop so I can turn it by hand, there's no roughness and there's plenty of compression. I'm not noticing any particular problems. As far as I can tell there's no reason to think it's anything other than mint and absolutely as new. Once again it's a lucky find. I got it for just under half the original sticker price, so it was $AU 300 (about $US 225) and for this engine in this condition, I'd have to think that's about as good as it's going to get. I doubt I'd find another one like it.
Thanks for the advice.