I am not familiar with this particular model but have heard a similar sound on machines that have a centrifugal clutch. The noise is caused by clutch mechanism.
Various fuel additives are available such as Castrol Valvemaster which is a lead replacement additive.
A good question and one that has been asked before. The answer is yes it is still classed as pedestrian operated, same as Barford Atom with trailer etc.
Thank you to everyone that has renewed their club membership either online or by post.
If you are wondering where your 2020 membership/insurance card is, I am waiting for them to arrive from insurers, hopefully I will have them next week. As soon as they arrive I will get them posted out to you within a couple of days.
Welcome to the forum, which is only part of the club, to be a full member you will need to pay either now or when free trial expires.
WD40 is not the best product for freeing rusted nuts and bolts, something like Plusgas is much better as it is a proper penetrating fluid.