Steve – if our mystery owner does not already have it, I would recommend he gets a copy of the relevant “Archives Du Collectioneur” publication …………..

It covers several models and I have found it invaluable for the 5HP.
The “Archives” publication for the “B14” is actually available in the technical docs pages of the TOC website. It might be worth checking but I guess it will not be as relevant as this one for a “B10”.
And, if he wants to contact me, I shall be happy to talk to him about likely spares sources etc.
B………..