Thanks for that, I pulled the plastic manifold off and the o-ring was damaged.
All the shops would have been closed, so I pulled out an assorted o-ring kit that I had and did the best I could to find one that was reasonably close.
Well now it starts pretty much straight away and there was plenty of power to cut the grass.
Thinking I should probably go out and buy the correct o ring next week as i'm not sure if what I used is even rated for petrol. I think it's probably a good idea to change the carby to manifold o ring as well while I am at it.
Are they a specific victa part obtainable only from a mower shop or will a bearing shop or similar be able to help me out? If so anyone know the correct sizes
Thanks