Lower unit oil-Black and smells burnt

SST

Well-known member
While getting my boat ready to launch, I also included changing the lower gear oil. I took out the upper screw and oil came out, so I thought there is no leaking oil. But I thought it was a little dark. Then pulled the bottom screw out and boy was it BLACK! Also had a steady stream of fine golden particulate. I began to smell the awful scent of being burnt. I had expected to see a change in color but not this extreme. I went back and checked my receipts and logbook, it was changed 2 years ago and only 90 hours of usage.

I have read some online postings and most boat owners don't consider this a major problem. Just keep changing the oil. One suggested changing the oil again in 20 hours to see if there is any substantial change.

I thought I would post here just to get an opinion. I'm only 1 day away from launching unless your opinions say otherwise.

Thanks.
 
We had the same thing occur a couple years ago with our Volvo and were right under 100 hours from the previous change. The mechanic who did the work told us that some units are harder on the oil than others (no rhyme or reason) and to be watchful for the first couple times out. We didn't have any issues.
 
I always did the change in the fall. Than in the spring, I found the oil was low, due to the air pockets came up over time. This is why you pump in the oil from the bottom of the drive. To help eliminate them.
 
The mechanic usually changes the oil when it goes in for repairs, so I've never seen this before. Once, I changed it and it came out very light blue. Not a hint of black. It was somewhat of a long time ago so I can't recall why I did it and what the service interval was. It was quite a contrast compared to the other day. I will start changing it myself at the end of the season.
 
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I had the boat out of the water for a minor check up including changing the lower gear oil. About 20 hours of use. He says it came out clean and nothing to worry about. Just change it every year. Which I will.
 
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