Hi Theo, Sorry for the delay been away with work.
Tried a new plug and ran the mower without an air filter and still the same symptoms.
When I pull the starter cord a puff of oil comes out the breather hose/ sit filter housing and its making its way into the carb and eventually into the cylinder. The new plug was very oily upon removal.
This is the first side valve Honda I have worked on and I cant work out why the breather would be spitting out oil.
I'd appreciate any suggestions you might have or any others!
Thanks
Jaffa.