Boat mechanic questioned me on my oil change frequency. I told him I changed it prior to bringing it to him. Upon further inspection he found sludge near the oil sump and it was partially blocked. He also removed several large chunks of plastic from around the sump. Has anyone ever seen or heard of this happening? We were thinking it was a something from the factory. The motor has 320 hrs with and I have done 3 oil changes. Thank you.