Hi Guys, new guy here with a question. Just drained my gear oil in a Yamaha f200i4. Using Amsoil marine gear lube since new 200 hours ago. On this 100 hour oil change the amsoil that goes in a light honey colour drained black. No sign of water intrusion just very black gear lube. Checked the oil drained for metal pieces with a magnet but only showed some tiny fragments ( expected). Not much on the drain plug magnet. Can any one explain the change from honey coloured to black in a 100 hr. oil change. Look forward to hearing from you. With thanks, trapper2
Amsoil marine gear lube
- Thread starter trapper2
- Start date
- Status
MolaKule
Staff member
Moisture will intrude regardless.
Also, the LG unit may have been operating at higher temperatures and higher loads than you know. The high temperatures would cause faster oxidation.
Also, the LG unit may have been operating at higher temperatures and higher loads than you know. The high temperatures would cause faster oxidation.
Last edited:
Aluminium Gear cases have a high flow of water over them like no other application. They actually run very cool
What did you run the 100hrs before, and what did it look like? The Amsoil should be one of the best gear lubes you can get.
Though I don't have much experience with the marine gear lube. I have used the automotive gear lubes a fair amount. I agree that being in the northern waters you should be running on the cool side.
What kind of boat and use are you using this under? Commercial, or recreational?
Though I don't have much experience with the marine gear lube. I have used the automotive gear lubes a fair amount. I agree that being in the northern waters you should be running on the cool side.
What kind of boat and use are you using this under? Commercial, or recreational?
Thanks guys for your responses. Still questioning the colour change. The first 100 hours I used the same gear oil (Amsoil Marine 80-90 gear lube) but had no colour change on draining it. At 200 hours I get the black oil. I don't believe it was overheat, but cannot be sure. There is no sign of the gear casing being hot. In any case would that turn the lube from honey colour to black? Cheers and thanks, trapper2
The boat is run recreationally approx. 100 hours a year. Used mostly for running as I have a Yam F8 kicker for trolling. Thanks again, trapper2
I have used Amsoil marine gear oil for the last two lower unit oil changes. I do this once a year in the fall. I maybe put 30 hours a year on my outboard (1998 Mercury 125 HP ELPTO 2 stroke). The old fluid was very dark on both of these changes but not milky. Not much for metal on the magnetic drain plug. I really don't know why the fluid gets so dark with not that many hours. You would think that fluid wouldn't get very hot being that the gear case is submerged underwater.
One thing to keep in mind is a boat motor is under the same strain as a car/truck going up hill all the time.
So the load factor is much higher.
So the load factor is much higher.
They do get hot, in addition to the load factor mentioned by oilboy, the exhaust gases come down and exit around the lower unit and out the prop. Is it possible it was under filled last change? Like motor oil, color is not a reliable indicator of its condition, but I hate to see it black also. Amsoil marine gear lube has been a highly regarded lubricant.
I would have the lower unit pressure tested.The seal might be allowing dirt and water in under the right condition. If you troll alot or run in muddy , murky water.If you have had fishing line wrapped around the prop at some point, that might have cut into the seal.Run the old oil thru a coffee filter, and see if there is any residual black stuff you can identify. My two cents.,,
I think you are ok. you are using a great product. I would not have it pressure tested... dealer will just say its bad and smile as he soaks you. run it till it stops.
Originally Posted By: BigCahuna
I would have the lower unit pressure tested.The seal might be allowing dirt and water in under the right condition. If you troll alot or run in muddy , murky water.If you have had fishing line wrapped around the prop at some point, that might have cut into the seal.Run the old oil thru a coffee filter, and see if there is any residual black stuff you can identify. My two cents.,,
Best is pressure and vacuum tested.
I would have the lower unit pressure tested.The seal might be allowing dirt and water in under the right condition. If you troll alot or run in muddy , murky water.If you have had fishing line wrapped around the prop at some point, that might have cut into the seal.Run the old oil thru a coffee filter, and see if there is any residual black stuff you can identify. My two cents.,,
Best is pressure and vacuum tested.
- Status
Similar threads
