Welcome Owenga
Firstly let me congratulate you on being "given" and Lister CS.
Refurbish it nicely and the unit will outlive you.
I can't offer any advice on the startomatic starter/generator but there are uses here who are quite knowledgeable.
The engines are very simple and a joy to dismantle and tinker with.
Check the bore, piston and rings.
Check the valve guides and seats. Lap the valve seats if everything else is ok.
Change the big-end bearing.
Post some picture as you go.
cheers,
veggie