YOU WILL NEVER GUESS....
All the starting problems were caused by the kill cord. Previous owner supplied with the wrong fit.
I only caught on as bought a new Tohatsu one because the old cord was past it.
Fitted today and suddenly engine fires in 2 secs. Put old one on again and it is difficult to start.
Ah well...its just had water pump refurb, new plugs, new fuel lines, new filter, carb stripped and cleaned, new drain and fill plugs, new seals, new thermostat, all moving parts greased, fuel system cleaned through, new gear oil, new trim tab, new trailer hubs and bearings and new winch.
Think I can assume its fit to go.