Thread subject: Whaler Central - Boston Whaler Boat Information and Photos :: Lower unit
Posted by dflynn12 on 04/14/08 - 11:02 AM
#1
I recently purchased an 1984 Boston Whaler 13 with a 1985 Evinrude 30HP. Before purchase I did take the boat on a trial run for about 45 minutes and the motor ran fine. Got us up to about 30MPH according to the GPS. Everything appeared great. After purchasing the boat I started to check spark plugs, clean up stuff and then checked the lower unit oil. What came out of the lower unit was like a dark grey or black sludge, it was very thick for oil. I've cleaned out the old oil the best I could by mixing 50% oil and mineral spirits together and running the motor with the prop turning slowly, so there was not to much of a load on the gears, on a hose for about 5 mins, then I put new gear oil in and ran it for about 20 minutes on a hose. After that I drained the oil and it was normal consistency and brown looking. I put more new gear oil in and and took the boat to the river and drove around over the weekend for about 2 1/2 hours. When I came home after the motor was dry I drained the lower unit oil and it was almost black but the consistency was ok. I've captured the oil in a jar and it has been sitting for two days but so far I cannot tell if there is a layer of water at the bottom. I was expecting the oil to be closer to brown/golden instead of blackish. Is it normal for the gear oil to look almost black?
Edited by dflynn12 on 04/14/08 - 11:26 AM
Posted by CES on 04/14/08 - 12:11 PM
#2
The dark color is okay, it's just the old oil mixing in with the new oil. What you should look for is a milky appearance in the oil. If you see white streaks or the oil is white/milky in color, then you have water leaking into the lower unit. Black oil isn't a big deal, a milky looking oil is a big deal and you're looking at replacing the seals in the lower unit if you did see evidence of water intrusion. If you don't replace the seals then you're looking at lower unit repair work.
Posted by Phil T on 04/14/08 - 12:20 PM
#3
I concur with CES.
Posted by Binkie on 04/14/08 - 7:56 PM
#4
I would repeat your procedure and test the oil again. Its possible the seals are not leaking but the oil was never changed.
rich
Posted by Derwd24 on 04/14/08 - 8:01 PM
#5
Could it also be possible that there's a worn component in there that's causing the oil to darken from attrition when even used for a short run?
Posted by CES on 04/15/08 - 5:51 AM
#6
Derwd24, you may be correct however there would be more symptoms other than just dark oil if that were the case. I think the oil is so old that it has degraded. If dflynn12 didn't get all of the old oil out then it is probable that the oil oil contaminated the new oil. He should replace the lower unit oil again and I bet he would have better results.
Posted by Derwd24 on 04/15/08 - 8:29 AM
#7
This is an interesting one. I've never re-changed the lower unit oil in that short an interval, and since there are no filters, etc, in that system, I wonder how long it normally takes for the oil to darken from regular use. Maybe it happens pretty quickly anyway in an average motor even with a complete drain? (I usually let mine drip overnight for good measure before refilling)