Really simple , basic service is fuel filter in the pump and the gauze thats fitted next to the glow pin. Just make sure when you fit the replacement you line it up , you need to make sure you don't block the small hole. If you want to go further then you will need a set of gaskets , pull the unit apart and decoke it .
Plenty of manuals available online or if you PM me I'll send you over the latest manuals and the part numbers you'll need .