BP1 aye,rare indeed >I had to look that one up on my microfiche .Strangely I don't have the IPL but I do have the shop manual which shows the gasket on what they term is "jet spray primer"
I wish I had a way to convert the fiche to a sendable file but as yet I don't .I've seen only one of this model that Dan Henry had and it didn't run .Weather it ever became operational or for that matter what ever happened with Dan I have no idea .I used to chat with him on the phone but it's been maybe 5 years since.