The foam air filter disintegrated when I touched it. Fortunately that happened whilst air housing was removed so nothing fell into the Carby. Seals, hoses are all in good condition. Gave everything a good WD40 bath and everything is moving freely and as designed. The fuel cap is stuck so I'll let the WD40 do its job and try again later. When pulling the starter it works fine and you can feel decent compression. They said it hasn't worked for a long time. Will check the plug, drop the oil and see what happens. What is a good substitute for the air filter?