Is there any way to get hold of a workshop manual or equivalent detailed
information about Honda lawnmower engines?

The engine on my machine has developed a leaky gasket. I am fairly confident
I could attempt the repair but there are several awkward unknowns. (At the
moment I cannot even see clearly how to remove the engine from its chassis
as the exhaust/silencer assembly is encased in a metal protective box which
seems to obscure all the fittings! This I could tackle if I had the
information to give me confidence to tackle the subsequent actual repair.)

The mower model is 2213 (ride-on type with hydro-elastic drive). The engine
model is GXV340K2 (4-stroke single cylinder petrol).

--
Frank