Hi, I bought a Poulan Farm Hand 20" saw used (very little). I filled it with bar oil and let it sit awhile after I ran it and it leaked quite a bit of the oil out. I've had several other saws of different makes that leaked also and wondered if this is normal, or can they be fixed. Also I wondered what size file should I use to sharpen this chain. I don't think it has been sharpened before. Thanks.