A paper element with foam would be better than just a foam filter but as long as you keep the filter clean it won't matter what filter you use ,
A good running mower can be bought for $50. these days on facebook marketplace, sometimes people just give them away for free, you just need to be careful how much you spend on parts as an air filter spark plug , carby and blades could cost more than $50.
I don't usually have to remove the main jet ,I just push fuse wire up the centre of the carby to clean it out then use compressed air and if the mower still hunts a little run the mower on some 98 fuel.
