How often do you guys check your lower unit oil? I had to put a new lower unit on my Marlin yesterday. We lost the port engine lower unit last week on the return from our 1 day snapper season. When we checked it, it was completely dry. We had changed it in March, only had 90 hours on it.
Lower unit oils
- Thread starter g0tagrip
- Start date
How do you loose a lower unit? I check mine only for leaks each I use the boat. To check for oil level would require removing top plug and I guess use something (piece of bent wire) to see the oil level. I just assume no leaks means it is full. I change every 80-100 hours or annually. I use synthetic lube.
SkunkBoat
Well-Known Member
- Joined
- Oct 12, 2017
- Messages
- 4,508
- Reaction score
- 1,614
- Points
- 113
- Location
- Manasquan Inlet NJ
- Website
- www.youtube.com
- Model
- Express 265
A Marlin...so you are not on a trailer?...
I can't imagine an LU could go "dry" in the water. If it Leaked you would see a slick. A tiny drop of oil on water is very noticeable. you could not miss it.
I would expect a noticeable drip with motors up. I would expect water in oil not "dry".
I suspect it was not correctly filled and it took a few months to self destruct.
Like most people, I fill at the beginning of each season and never check the level again til the boat is hauled for the season.
If you notice a leak, it needs to be hauled and fixed ASAP.
It can't go dry by use.
I never wait for spring. Always check the LU for water at end of season so you know if you need to fix it before spring.
I can't imagine an LU could go "dry" in the water. If it Leaked you would see a slick. A tiny drop of oil on water is very noticeable. you could not miss it.
I would expect a noticeable drip with motors up. I would expect water in oil not "dry".
I suspect it was not correctly filled and it took a few months to self destruct.
Like most people, I fill at the beginning of each season and never check the level again til the boat is hauled for the season.
If you notice a leak, it needs to be hauled and fixed ASAP.
It can't go dry by use.
I never wait for spring. Always check the LU for water at end of season so you know if you need to fix it before spring.
Last edited:
- Joined
- Mar 1, 2006
- Messages
- 3,027
- Reaction score
- 1,351
- Points
- 113
- Location
- Berea, KY/Cross, SC
- Model
- Seafarer
Did you change it or did a service facility change it? Should never "just" leak out. Replace washers on LU screws? Forget the bottom washer? If seals were bad, you would have water inside instead of "completely dry". If you changed it, did you forget to refill it, it could happen. I change mine out the end of season as well as a full service that I do, irregardless of hours used, cheap insurance on a substantial investment.
- Joined
- Mar 1, 2006
- Messages
- 3,027
- Reaction score
- 1,351
- Points
- 113
- Location
- Berea, KY/Cross, SC
- Model
- Seafarer
That tells me the lower or both washers were bad or not tight. If lower was bad, still wouldn't leak out because of suction, no way for air to get in unless it's a combination of factors,,, bad/no washers, drain screws loose, seals bad,, all contributing factors to "completely dry". Along with not refilling after draining.
If by “dry” you mean no oil and/or water, then it didn’t leak, it wasn't refilled after draining. Annually or every 100 hours I do mine and if I find water (milky oil) I fix the leak.
Hookup1
GreatGrady Captain
- Joined
- Oct 16, 2007
- Messages
- 3,035
- Reaction score
- 855
- Points
- 113
- Age
- 70
- Location
- Cape May, NJ
- Model
- Islander
I change mine every year. It's drained into a container to look at how much was in it, if it has water, if it has metal particles. Fishing line, especially braid, can get around the shaft and compromise the seal. The washers are replaced every year and tightened with a special tool. They are hard to tighten and people do leave them loose. They don't fall out but they could allow fluid to be sucked out in the vacuum under power. I lost a lower unit a few years ago to loose washers and exchanging oil and salt water. Full of chocolate milk oil and metal particles.
It's also a good practice, although I don't do it every yer, is to use a vacuum gauge and a pressure gauge to test the lower unit before filling. Instruction are in Yamaha service manual.
It's also a good practice, although I don't do it every yer, is to use a vacuum gauge and a pressure gauge to test the lower unit before filling. Instruction are in Yamaha service manual.
Last edited:
Sardinia306Canyon
GreatGrady Captain
- Joined
- Oct 11, 2023
- Messages
- 522
- Reaction score
- 101
- Points
- 43
- Age
- 60
- Location
- Island of Sardinia
- Model
- Canyon 306
My Canyon is in a slip so i can check LU Oil only when boat is on a lift or lifted out and on a maintenance rack,
and that happen all 100 hours.
I usually open the lower screw to drain a few drops to check for abnormal shavings or water if i have to pull her before 100 hours,
otherwise i just change the oil.
I made a test on my Suzukis in Costa Rica with Castrol Syntrax full synthetic gear oil as even after 100 hours mineral gear oil was black ans smelled burnt on all 3 Suzukis. The Syntrax came out same honey color as new after 100 hours so i kept using it and will probably continue use it an my Canyon. Yes, i am aware that the Syntrax is not a dedicated outboard oil, the question is if that really matters.
LU Oil should be changed end of season or at least drained a bit to check it's state as o one would like to have water/humidity in oil and engine is 6 months in storage.
However i started to do the full maintenance before boats go in storage just to have it done and to know that they "sleep" with fresh oil and greases, and that let me sleep better to.
Chris
and that happen all 100 hours.
I usually open the lower screw to drain a few drops to check for abnormal shavings or water if i have to pull her before 100 hours,
otherwise i just change the oil.
I made a test on my Suzukis in Costa Rica with Castrol Syntrax full synthetic gear oil as even after 100 hours mineral gear oil was black ans smelled burnt on all 3 Suzukis. The Syntrax came out same honey color as new after 100 hours so i kept using it and will probably continue use it an my Canyon. Yes, i am aware that the Syntrax is not a dedicated outboard oil, the question is if that really matters.
LU Oil should be changed end of season or at least drained a bit to check it's state as o one would like to have water/humidity in oil and engine is 6 months in storage.
However i started to do the full maintenance before boats go in storage just to have it done and to know that they "sleep" with fresh oil and greases, and that let me sleep better to.
Chris