This is what the nylon filters on your petcock should be like. Ask on here if they are missing - you might strike lucky... or motor mower parts stockist may be able to assist. If you rely on the metal strainer gauze inside the tap body on it's own it will get blocked. Might be worth checking that it is there and intact if the other two are missing.
Dont want any bits getting in those refurbed carbs matey.
Cheers from Mark
