Thanks , I have a genuine manual and a clymer one so will study both closely. I had planned to make a puller for the flywheel so will get on with that too as I am planning to stay on this side of the pond this year.

Well I have one you can borrow if you want a pattern.

Thank you for the offer, I have a spare flywheel from the basket case to use to gauge the thread so I should be ok however don't hide yours away just yet.

I have a Sears (McCulloch with different cowls) that has the same "special" maintenance port

My all time great find was a Merc 50 for sale on ebay, where the starter spring, or pawls, had broken. The enterprising owner had taken a cutting tool and removed the stepped section of the upper cowl, fittting a fetching pair of hinges and using the emergency cord under the faceplate to start it on the flywheel each time.

Petrolhead and me wept with laughter for days about that one, was an anti-depression pill. For a long time I had the pic, but it's gone, sadly.