Hi Guys, I did my 100 hour maintenance on my Yamaha 150 outboards last night and replaced the oil in the lower units. The oil from the lower unit of the starboard engine was fairly clean and almost new appearing. The oil from the lower unit of the port engine was absolutely black, almost like engine oil that had been neglected for several years but these are newish engines. There are no signs of leaks and there was no evidence of water contamination, etc.
Operation including shifting is completely normal as far as I can tell. Any thoughts? Should I be concerned?
Thanks so much!