Rislone stop leak (silver bottle with blue bit) works really well for sealing leaks you can't be bothered fixing.
Can get it about $8 on special and get about 4 mowers out of each bottle. But give it a really good run and flush as you have to use it every oil change for it to work. You want a clean sump so the oil doesn't go dirty straight away
What are you using for an air filter?
