Petrol Lawnmower - Honda Izy 415 C2 - revving up and down

Having a issue with the Honda Izy. It rev's up and down and eventually cuts out. After a while of restarts it just cuts out all together.

I've checked the air filter and given it a clean, although it was already quite clean.

I've checked the petrol

Next thing to check is the oil.

One thing this page says at the bottom is to tilt the lawnmower on it's right side (away from the air filter) as this takes any air bubbles out of the system, worth trying.

Found this manual on a different model, will need to check what sort of oil it takes though.

I've seen a few videos which suggest it is the Carburettor, something clogging it up. Probably needs the air filter taking off first then the carb. Need to get some carb cleaner though.

Found this website which sells parts for it, heres a service kit, and heres a gasket kit