I have ordered iridium & standard plugs. Ebay you can get 4 standard plugs for the 35 hp briggs for around £7.50 incuding P&P
The price of iridium plugs are a different story, but they have to be worth a try

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I have also ordered a new fuel primer bulb as mine is starting to go stiff, as its been on there for 30 months.
Fuel filter.
I need to suss out the part numbers for the air filter and I think I may see if I can get a new kit to refurbish the Briggs fuel pump, as that has done about 50 hours so I think it has to be worth changing while I am servicing the engine.
Also need to find the oil filter number, as I fitted a genuine Briggs last time & it cost me over £20 which is a rip off.