Mtd Lawn & Garden Equipment Engine Crankcase Breather Filter Spring 951-12250 2.25 x 1.00 x 1.00 Genuine OEM. This is a Genuine OEM MTD part. This crankcase breather filter spring (part number 951-12250) is for lawn and garden equipment engines. Crankcase breather filter spring 951-12250 holds the breather filter inside the crankcase housing. Wait until the ... - Mtd Lawn & Garden Equipment Engine Crankcase Breather Filter Spring 951-12250 2.25 x 1.00 x 1.00 Genuine OEM.