Any oil of that rating should be OK but don't mix synthetic and mineral oil because it can emulsify into a nasty mix.
Thanks for that. So if I stick with the same oil (semi synthetic) I can use that with no problems then?
It may pay you to check the oil spec.....it should state what rating the oil should be eg SF or greater....I believe S means spark ignition and the second letter denotes the detergent level with A being the lowest......My old generator required a fairly low spec oil.....using a higher spec than required can cause trouble due to a higher detergent level.
What is the make of generator or engine??? you may find more info on the web...some of which may even be right!!!
Thanks Gareth. It was from B&Q - Power Performance I think it was called. The box is in the car and its too dark and scary outside to go and look...
It's new name is Jenny - Jenny Raytor... A single bell tolls and a tumble weed blows across my path... I mean towpath...