Changing Gear Oil

[CaptainTDawg]

So, i am stuck in limbo on what to do. Yesturday, i unsiezed the vent plug on the lower gear case to check the Gear Oil. Right as i backed out the screw, the olive green oil started pouring out. I quickly plugged it back up. The oil looked in good condition, no water or metal particles in it. But im not sure if i need to change it. Last year, i used my boat about 3 times during the season, for a total of about 10 hours of runtime. in my manual, it says that the gear oil needs changing every 100hours of use or 6 months (I.e every season). So my question is does the gear oil go bad after 6 months? Is that why u need to change it every season? Or can i just use my existing gear oil since it has so little hours from last year? Thanks in advance - C. TD

 

[minuteman62-64]

Don't know about your motor, but, mine only takes a few ounces of gear oil to fill. If I'm going to make the effort to bend down to remove the plugs I'll go ahead and change the oil while I'm down there. Pretty cheap insurance.

 

[nwcove]

So, i am stuck in limbo on what to do. Yesturday, i unsiezed the vent plug on the lower gear case to check the Gear Oil. Right as i backed out the screw, the olive green oil started pouring out. I quickly plugged it back up. The oil looked in good condition, no water or metal particles in it. But im not sure if i need to change it. Last year, i used my boat about 3 times during the season, for a total of about 10 hours of runtime. in my manual, it says that the gear oil needs changing every 100hours of use or 6 months (I.e every season). So my question is does the gear oil go bad after 6 months? Is that why u need to change it every season? Or can i just use my existing gear oil since it has so little hours from last year? Thanks in advance - C. TD

if the motor was vertical, and it was the "vent" plug you unscrewed to get oil to pour out.....it was either overfilled or you opened the drain plug. either way, since youve gone that far, you might as well finish the job. ( if the plugs have crush washers on them......you dont have much of a choice but to do the job!) jmo

 

[Sea Rider]

If it's the first oil that came factory delivered with engine you must change it each 10-20 worked hours from new. It's a pity to discard such a immaculate clean oil, will depend entirely on you if changing or extending its life 10 more hours. A test that haven't had the opportunity to do is check the amount of gear oil factory filled on each lower leg. Could be a minimum amount just for break in period, that's why it's recommended to be changed at stated intervals, but that will never know for sure untill properly measured.

Happy Boating

 

[Outsider]

in my manual, it says that the gear oil needs changing every 100hours of use or 6 months (I.e every season).

And your question was what? I think the inference means every 6 months even if it isn't used at all. You don't have to ever change it, buuuut ...

 

[robert graham]

I change my lower unit oil once a year and it's always been nice and clean/clear as I drain it out....so I know that I don't have any leaking seals.....and that's really the reason for draining the fluid...to check for leaking seals. If you run in salt water it's very important that your seals don't leak at all....

 

[dingbat]

And why is it that Jiffy lube says to change your oil very 3k miles yet the manufacturer says 7.5k miles? After break in, there is absolute no need to change oil very 100 hours or 6 months except for cases of water intrusion. If the seals are good, there is no reason why the oil couldn't go 1000 hours or more. I check my oil 2-3 times a year, change it only once...usually 200-250 hours between changes

 

[Sea Rider]

Dingbat,

Would you say that your leg oil changed as stated at each 200-250 assume metered hours comes out immaculate clean as when was brand new ? Definitely not, usually dark colored or contaminated with exhaust combustion dregs that get's in gear box through water pump or adjacent sides. Will be a good starting point to check out at a lab the properties in terms of viscosity and other tech parameters between brand new and 250 + worked hours.

If happens that at 200+ hours oil has lost viscosity properties and the ability for the elements to hold to/lube well internal gears on the medium/long run, we don't know that yet, will definitely be contributing wearing faster your gears that changing it at half or slight + hours than you change yours.

Bottom line, gear oil is relatively cheap, why not change it as factory stated or tad more..

Happy Boating

 

[82rude]

my etec as factory stated. every 3 years.

 

[robert graham]

But, have you ever seen the insides of a lower unit that leaked some saltwater past a seal or a drain/vent washer?....they turn black and the bearings and gears all sustain serious damage....so the changing of the lower unit oil is mostly just a check of the seals.....so far when I've drained mine the oil looks pretty much new....use it for my chain saw oiler or other.....

 

[dingbat]

Dingbat,

Would you say that your leg oil changed as stated at each 200-250 assume metered hours comes out immaculate clean as when was brand new ? Definitely not, usually dark colored or contaminated with exhaust combustion dregs tha get's in gear box through water pump or adjacent sides. Will be a good starting point to check out at a lab the properties in terms of viscosity and other tech parameters between brand new and 250 + worked hours.

If happens that at 200+ hours oil has lost viscosity properties and the ability for the elements to hold to/lube well internal gears on the medium/long run, we don't know that yet, will definitely be contributing wearing faster your gears that changing it at half or slight + hours than you change yours.

Bottom line, gear oil is relatively cheap, why not change it as factory stated or tad more..

Happy Boating

Let put things into perspective.....Not unusual to put 60-70 hours a week on the boat during prime fishing season. I should be changing my LU oil every other week?

My LU has 2500+ documented hours on it. Oil changed once a year, avg. 200-250 hours for the past 10+ years. When is the accelerated wear going to start?

 

[pckeen]

Since you removed the plug, the crush washer will need to be replaced, so should change the oil now too.

 

[JimS123]

Since you removed the plug, the crush washer will need to be replaced, so should change the oil now too.

I "inspect" the washer and replace it if it looks damaged or worn. I wouldn't exactly call it a "crush" washer because that would connote that it only has 1 use. In 50 years of owning outboards I think I might have replaced a washer twice, and i have NEVER seen water in any of my lower units.

Water settles and will come out first. Crack the drain open and if clear green oil comes out, squirt a fresh ounce in and butten her up again. Motors i run 20 hours a year have oiul that looks like new and get changed evry 100 hours or so. If it comes out black it gets changed.

My current I/O lower unit has 1250+ hours without any issues.

 

[bilge rat jim]

Just a cupla points- If you only removed the vent screw, how do you know what's in the bottom of the gear case? You really should remove the drain screw and inspect for water intrusion, and abnormal wear which will be indicated by metal filings. Also, the topic of whether or not to replace the blue seals (crush washer, plug gasket, whatever)- These seals are designed for one use only; however in a lot of cases they can be reused. But to save less than 2 bucks are you willing to ruin your gear case?