Marine Gear Oil for lower units

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Dec 31, 2017
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Location
SE British Columbia, Canada
Here's a couple from Quicksilver. Any other favourites out there?

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Amsoil here too. I go 2-3 years on mine since I only put on 20 hours a year. I check for water every fall/storage.
 
Originally Posted by Mainia
Amsoil here too. I go 2-3 years on mine since I only put on 20 hours a year. I check for water every fall/storage.


How are you able to check for water contamination?

There was a UOA posted a while back from a Bravo drive with high oxidation and low hours. Thinking out loud, if the boat was kept in the water vs trailered in and out every time, that may make a difference too?
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I change my lower unit lube with super-tech every fall on my Mercury 115 and my 9.8 and they are both 4 strokes. It's always a bit of a mess but I get it done.
 
^^ oops, I should point I went with the Mobil 1 DELVAC 75/90 gear lube (recommended by Volvo), I think there is plain old Mobil 1 gear lube too but important to note the difference in my choice of words
 
I have no favorites. They say synthetic is more water damage resistant . The only thing I recommend is preflight check of your drive oil tank every use. If you don't have one put one in and DO IT. I partly remove mine on the trailer a couple times a season and let a few drops out looking for water ( it'll be on the bottom at the plug) or milkshake.
The real killer is fish line. Guess where everyone fishes........boat launch and surrounds. ... . Mono will wrap round and cut that prop seal nicely. the new braids will do an even better job. You won't ever feel a thing but when that top gear set comes out of the oil there will be a funny slight vibration followed by high revs going no place...©. Then 5 lbs of gear meal you can spoon or suck out with a straw...¿. That clear bottle will🤞🻠Hopefully let you see it going down before it goes bang. That's the theory anyway....
 
I just did a test of water contamination using regular gear oil, and marine gear oil. The test was for water emulsifying- will the gear oil keep the water in suspension ? All marine drives get some small amount of water contamination, so the goal is to keep it from damaging the drive.

Well- the marine gear oil did exactly as was claimed- it kept the water in suspension for over a week, while the regular gear lube let it settle to the bottom in hours. I used about .5 oz of water per 8 oz of oil for the test. I might get around to posting pics.
 
Originally Posted by alarmguy
^^ oops, I should point I went with the Mobil 1 DELVAC 75/90 gear lube (recommended by Volvo), I think there is plain old Mobil 1 gear lube too but important to note the difference in my choice of words


Its nice they gave you a less expensive automotive option as well. Just goes to show it doesn't have to be marine grade.
 
My 85 Volvo 290 drive uses engine oil. I use diesel oil in it.


I pull my boats out of the water when were done playing with it. I use regular gear oil that I have sitting around. That's for the last 2 other boats that required gear oil.
 
Originally Posted by Bluestream
Its the same oil as automotive, no need to pay more.


This is a false statement- in many cases automotive gear oil is not the same as marine oil. See my opening statement on water emulsibility. That said, marine gear oil is pretty common and you can get it from many different vendors.
 
Originally Posted by dlundblad
Originally Posted by alarmguy
^^ oops, I should point I went with the Mobil 1 DELVAC 75/90 gear lube (recommended by Volvo), I think there is plain old Mobil 1 gear lube too but important to note the difference in my choice of words


Its nice they gave you a less expensive automotive option as well. Just goes to show it doesn't have to be marine grade.


Not really less expensive, I think? But easier to buy. Still cost me over $40 delivered to my door for one gallon.
 
I always use Mercruiser high performance gear lube. It takes 2 quarts and it gets changed once a year. You can get it at Walmart. Replacement outdrives are thousands.

$20 a year for gear lube. Why scrimp to save a few dollars?
 
Originally Posted by Bluestream
Its the same oil as automotive, no need to pay more.


This is a false statement- in many cases automotive gear oil is not the same as marine oil. See my opening statement on water emulsibility. That said, marine gear oil is pretty common and you can get it from many different vendors.
It’s important to note the manufacturer of the drive unit.
Volvo Penta only recommends their gear oil or Mobile Delvac 75/90 not a marine specific gear lube.
 
It’s important to note the manufacturer of the drive unit.
Volvo Penta only recommends their gear oil or Mobile Delvac 75/90 not a marine specific gear lube.
I have never owned a Volvo stern drive. I looked up the specs and the product does not mention any "marine" use or Volvo spec, but it does seem to be a high quality product.
 
I have never owned a Volvo stern drive. I looked up the specs and the product does not mention any "marine" use or Volvo spec, but it does seem to be a high quality product.

This is my first Volvo Drive ever and I have been boating for ummm ... over 4 decades.
Owners manual specs Volvo Gear Lube of Mobile Delvac Synthetic 75/90 for the SX drive.

Im partial to Mecruiser ONLY because I know them so well, with that said, the Volvo SX, wow, very impressed so far, for the most part. Either way, to me outdrives are a PITA as time goes on and they age.
 
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