Outdoor Power Equipment (Lawn Mowers, Snow Blowers, Chain Saws and more) Discussions

I was changing oil on a GX340 engine on my snowblower. The manual says it holds 1.1 quarts of oil (which I read as about 35 ounces) Yet, the manual also shows that you fill up the crankcase until it's touching the threads for the dipstick. This is pretty common in the GX line (same in the GX160). However, if you add 1.1 quarters, the oil comes halfway up the dipstick, nowhere close to the threads. If you fill it until it reaches the threads, it's closer to 1.4 quarts, or 45 ounces. I am frankly baffled by how much oil this engine needs. Thoughts? Also, this winter is the first the engine has really worked for more than an hour, and when I changed the oil, I could see flecks of metal (microscopic) glinting in the sun. I am inclined to add a magnetic drain plug to the machine, and was wondering if anyone had any opinions on doing this.